Your character would likely not be found guilty of anything (based on what you have shared with us so far), but I can definitely see where she could be arrested and held without bail while awaiting her trial, especially if she's living in a very "law and order" type of state such as Texas or Alabama. The fact that she's associating with terrorists and, frankly, her skin color would make law enforcement very suspicious of her. Every state has different laws regarding terroristic crimes and the federal government has their own laws.
I can offer a view of how I would expect it to go down in Alabama (where I practice law).
She would likely be arrested with much fanfare. The sheriff would have the media there to witness the arrest and several dozen deputies would be involved. Local police may also be involved as well, but since the sheriff is an elected position, he would want to lead the arrest. If she cooperated, they would not harm her during the arrest, but she would be handcuffed and the area immediately around her would be searched. If she was at home, her house would be searched too. There would be a press conference after she was jailed wherein the sheriff would spend 5-10 minutes talking about how horrible she is and how great his deputies are. Meanwhile, she would be processed by the correctional officers, which involves collecting all of her biographical information, fingerprints, DNA sample, taking her photograph, strip searching her and taking her to her cell.
Most county jails in Alabama hold both males and females in the same facility, although efforts are made to segregate the sexes. It is likely that she would be held separately from all prisoners; high-profile prisoners are usually kept by themselves in the jail because the sheriff, who is also responsible for maintaining the county jails in Alabama, won't want the bad press or any investigations conducted if something were to happen to a high-profile prisoner. She would have limited access to everything and would be kept in her cell most of the day. Each prison is different as far as the specific rules regarding how prisoners are treated. For example, prisoners in my home county cannot have any reading materials; there is a very poorly stocked library in the jail, but the books cannot leave the library. The only real diversion they are allowed to have in jail would be a pencil and some paper to write letters.
Ok, after she's locked up, she would get a bond hearing within 72 hours. These hearings are usually held on Monday/Wednesday/Friday. Better funded jails do it via television; prisoners are taken to a special conference room and see the judge on a television screen and the judge sits in his office and can see the prisoner on his television screen. Poorer courts hold the hearings either in the jail or in the courthouse. If she has not been able to hire an attorney by this point, she will represent herself at this hearing. The judge will converse with her to some degree to make sure she's being treated decently. For example, if she had a busted lip during this hearing, the judge would ask about it and may investigate it a little if he felt that the correctional officers were abusing her or were allowing her to be abused. However, that will be the extent of the judge's compassion and he will either not allow her to have a bond or will set it extremely high($250,000+) due to the nature of the charge (the bail schedule would suggest that her bond be set between $2,000 and $30,000, depending on what she is charged with exactly, but judges routinely ignore the bail schedule). She will be allowed a phone call after this to try and make arrangements to make her bond or just to contact family members. If the correctional officers do not like her, they can frustrate this process rather well (many of my clients complain that they are told that the phone is broken or the guards will only allow 30 second phone calls).
Her first court appearance would be about 30 days down the road for a preliminary hearing. At this time, if she has not been able to hire an attorney on her own, the court would appoint an attorney for her (either through a public defender's office or a local attorney would be appointed). She would be allowed to briefly meet with her attorney but her preliminary hearing would likely be continued another 30 days so her new attorney can have time to review the case and decide a course of action. If she has been able to retain an attorney, she would either have a preliminary hearing that afternoon (where the judge must decide if the police had probable cause to arrest her) or her attorney would stipulate that the police had probable cause and would waive the case onto the grand jury. Most attorneys would just waive the case on in this situation because a judge is not going to dismiss a case of this nature (and because law enforcement can just go to the grand jury later on and re-arrest her again). Note that appointed attorneys are either very young or not very good attorneys. A public defender is usually a good criminal attorney but they usually have more cases than they can handle, so they don't often to get work on cases for as long as they want to.
She would not see a courtroom again for a few months after her prelim. The case would be presented to a grand jury to decide whether or not to indict her for whatever crime she is charged with. Neither her nor her lawyer get to be at this presentation, so it is very easy for the prosecution to have someone indicted. Smaller courts only have grand jury sessions once or twice a year while larger ones usually have grand juries once a month. She will eventually receive notice of a court date after she is indicted. Her lawyer will not be able to do much for her until after she is indicted, so this is when she will likely be most frustrated with her attorney.
Her first court date after her indictment will be her arraignment, where she formally pleads not guilty. This is also the first time the prosecution will begin really negotiating with her attorney for a plea bargain. Because she is charged with a terroristic crime, the prosecution will insist on her doing some jail time. If her attorney intends on trying to lower her bond, this is the time that can be dealt with (some courts will have another day when bond issues can be handled) If a deal can't be struck that day, her case will be put off 2-3 months. She will then be on a status docket. This is when both sides let the judge know where the case is (specifically, if there are any issues that need to be resolved and whether or not a trial will be needed). Either way, the judge will set the matter off another 2-3 months for either another status docket or for a trial docket. Note that if a court has too many cases or if a case is very complicated, it is not unheard of for a criminal case to sit on a status docket for 2 years. When her case finally reaches the trial docket, she will have her trial within a few months. In my home county, for example, the 60 oldest cases on the trial docket must be resolved within the next "trial cycle," which generally last three months. Almost all cases reach a plea rather than go to trial. It is not uncommon for only one case to go to trial during each trial cycle.
While all of this court stuff is going on, your main character is just sitting in jail. She will be bored out of her mind. Usually, she can have visitors only one hour a week, on a weekend, and at a predetermined time. In more modern jails, visitors are not even allowed into the jail and must communicate via a television set-up from the lobby. Her attorney will be allowed to visit most of the time and will get to meet with her in person at the jail in a special conference room, but an appointed attorney usually won't come to visit more than once. Even a retained attorney usually has little reason to visit a prisoner more than once or twice unless the case is unusual (or he's being paid by the hour). She will have to buy everything that she needs from the jail store at very high rates. If she can't afford a necessity, it will be provided, but either it won't work very well or she won't want to use it. If she needs medical care, she will only be allowed to see a nurse (who can then send her to a doctor) and the nurse only works part time. Cruel guards can also "forget" about sick prisoners for a few days too. Medication is not distributed very well. Many of my clients will go without necessary medications for days at a time for various reasons. However, she will actually receive better care than most prisoners because of her special status.
If she is allowed into the general population, she will have an easier time in jail. Most county jails have a wide variety of prisoners who are awaiting trial. If you are convicted of a felony and have to serve any time over a year, you get transported to a state prison, which is where other prisoners can really cause problems. In county jails, however, the chances are significantly lower that she will run into any serious altercations. She will encounter some racism, but it would be unusual for her to actually be in fear for her life. The food will be bland and not so good, as noted in Maryn's post.
Because of the political nature of her case, it is likely that she will have to go to trial, plead guilty or be forced to prove her innocence. A prosecutor would be very hesitant to dismiss this type of case (as they may appear to be soft on crime). It would be very difficult for her to prove her innocence because the charge would like be something akin to conspiracy. The prosecutor would likely make her an offer that makes law enforcement look good but still be something she could live with. For example, they could make her an offer where she pleads guilty and gets sentenced to 10 years but only has to be in jail for one year. She would also receive lots of advice from other prisoners (if she is allowed to have contact with them) on what to do and most likely her attorney would want her to take the deal (because it would be less time than what she would get if she was found guilty by a jury and because most attorneys are scared of trials). If she went to trial... Well, I'd need to do another post about as long as this one to explain the trial process in enough detail to be useful to you!
As far as the crime she would likely be charged with, in Alabama it would likely be Providing Support to a Terrorist, which is a class C felony (unless her assistance was worth more than $1,000, in which case it would be a class B felony). The range of punishment would be between one year and ten years in jail (two to twenty if it was a class B felony).
I hope this is helpful. I know I've thrown a lot at you, but I assume you would rather have too much than too little! Also, like I said at the beginning, this is just based on my experiences in Alabama and it will be different in different states. The federal system is even more different, but I don't do much federal work, so I can't offer much help there. Good luck!