Dont worry much about the instate "quota". Give it a shot, coz you still have a while for fall semester to begin. The "quota" for fall is larger than that for spring.

As far as research/teaching assistantships are concerned, you have better luck if you are a graduate student or PHD. Some undergraduate research positions are available, but you would need to "know" your professor before getting appointed (generally speaking, assuming you are no Einstine). You can leave that part for your post admissions checklist.

Im a student at UTA and quite frankly dont think its worth $7000 a semester. If you get a scholarship and end up paying around 3k a semester, Id say thats a fair bargain.

Best of luck n c u in school :P