I am a international f1 student. I have filed my taxes through turbotax.com, I had got 300
$ tax return which was only for american citizens.turbo-tax does allow you to put your nationality but I think what I did was wrong. If so is there anything I can do to make it right, pay some fines or sth? Will this cause a problem in the future while I apply for my status change

You need to amend your return.
Fill out form 1040X
http://www.irs.gov/pub/irs-pdf/f1040x.pdf
and a complete non-resident alien return
http://www.irs.gov/businesses/small/international/article/0, id=96477,00.html
If you owe money, send a check together with the return stating your name, address, SSN, tax year and form you file
If you do it in a timely manner (before April 18th), there will be no penalty and no problems for the future either, as this was a honest mistake.