Hey,
It sounds like you're doing everything right. A couple of things you could look into also...
Image Comics - You can send them a sample of the comic (minimum 5 pages) , exact guidelines on their site. They specialise in publishing comics and look at unsolicited submissions. So you can potentially send it to them while you're waiting to complete the issue. The good thing about Image is that you get to keep ALL the creator rights to your work, but their standards are pretty high.
The following is a recently updated list of pretty much every comic book publisher out there, if you want to follow that route :
http://www.optimumwound.com/the-sub...comic-and-manga-publisher-in-the-universe.htm
Also you should consider Dark Horse comics as they have a good reputation.
I'm not the most experienced out there, but if you need a bit more feedback I have time on my hands and will be happy to beta read your script for you.
BTW, if your artist is looking for more work, I'm in a similar sort of situation to yourself. I won't be able to pay her much more than what you are(maybe a little more), but if she's interested in potentially working on something else as a next project please ask her to drop me a line and I can tell her what the project is about.
Again, best of luck with the project.