Again, Alex - please bear in mind I'm not really familiar with self published as it's done best in the UK. I'm sure there are some variations from "best practices" over here in the US (although I'm always interested in hearing about those!). So my advice is US-based; you'll need to tweak it for your own situation.
What do you intend to do with the 200-250 copies? Over here, it's quite hard to get SP books into bookstores. It can be done, but usually in small enough numbers that using a POD (print on demand) service like Lightning Source is more economical. There are some notable exceptions to that, of course (some folks have done short runs like you mention and sold them all quite well). POD gets you into the major online bookstores, allows you to easily sell from your own website, and lets you order fairly cheap copies to use for sales at conventions and such.
Packages. Hrm. Again, this may be colored by a US bias. Over here, the "self publishing help" companies are mostly scams run to take advantage of uninformed writers. They tend to overcharge, often do a mediocre job, and generally should be avoided (talking about the subsidy presses here: Author Solutions and their ilk).
Over here, it's often better to piece together your own "package" from various providers. There are some service companies which will do editing - covers - and print formating for a one time fee (those are the three critical services you need to learn to do or hire out).
You can find some cover artists over at the Writer's Cafe of Kindleboards. Caveat emptor. Some of them are very, very good. Some are not. DeviantArt is another good site to check - look for artists you like, and email them asking for a quote. Sometimes you can get better rates from a newer artist looking to make her name. Over here, we have copious numbers of college students who are quite competent at art, and will often do work for less than you might otherwise charge.
But overall, remember that most of your sales (90%+ for most SP novelists over here) will be ebooks. And ebook covers tend to do best as simple, iconic art. Which are easier to produce than big, gorgeous paintings. The complex, wonderful covers often seen on print books simply don't show up well at postage stamp size. And since that tends to be the size they are viewed at by people buying even print books from online retailers, the same holds true for POD to some degree.
Hiring an editor is a sticky bit. Yes, ideally, you really want one. Content editing - what you're talking about, with plot holes, repeated words, things that "don't make sense", etc., can be *extremely* expensive to do well. Really, you're looking at a couple thousand dollars minimum, from most people I've seen.
Copy editing - typos, bad spelling, grammar fixes, punctuation, etc. - tends to be much cheaper. You might be able to get away with spending as little as $250 or so on copy editing, if you write clean copy in the first place. If you're going this route, you need to rely on some other source for "content editing" - many writers use beta readers for this purpose. Some of the online crit groups can also work for this, to some degree. It's NOT as good as competent content editing from a pro, but if you cannot afford that, it's a way that works for many.
Best of luck. I'll answer other questions as best I can if you have any.