I think you are asking question that are ahead of time. Learning Turkish is one thing, but being able to learn Turkish at the level of university classes is a whole other thing. Secondly, you need to figure out WHAT you want to study. Not every university is the same, they do not all offer the same programs, and thus I can´t tell you what your tuiton would be.

You should figure out, do you want to study? Using a study as a means just to stay in Turkey is not the best of ideas. It would be better to just find a job, for example as an English teacher (since you are a native) if you get your TEFL (or a diploma like that). After you figure out, do you really want to study, than figure out which subject. Than figure out which universities offer the program, and than which universities have the best reputation in that program. You seem to be focussed on money and residency permits now, instead of the more basic important questions that you have to ask yourself first.

Here is the fees of private universities last year.

http://freeaider.blogcu.com/2009-2010-ozel-universite-ucretleri/5802833