Obtaining a student visa is not a very easy process. First, you need an I-20 form from the university. Before that, the university should either provide the assistantship or request the proof that your wife has enough costs to cover a minimum number of credits per semester (9 or 10 for graduate student). The tuition is quite expensive as you may know, especially these days when it continues to skyrocket due to the budget deficit. Receiving the assistantship would first involve contacting the desired professor and getting approval from him. Not so easy to do either.
The bottom line is that if you regard getting F-1 visa for your wife as a way to bring her here, I would not count on it. Unless, of course, you have a lot of money which you indicated you are not willing to spend. So, if I were you, I would just wait for the naturalisation and then file I-130 and I-485 - the proper and the most realistic way to go.