Tax question for those more in the know than I?

Ok so I graduated college this June, and I decided this is probably the year I should file my own taxes (my Mother has been doing them to this point). Well I just filled them out (using Turbotax) and I put in my tuition paid for 2009 (about half of what it was the rest of my years in school). Well this gave me a HUGE increase in my refund (over half of my refund is from this tuition paid credit). Well I called my mother because I’ve never received a big refund (a few hundred dollars normally, vs 1400 this year). She informed me that she has never listed the tuition paid in any of my previous tax returns.

Quick facts that may help you answer this:
-This tuition was paid by student loans, and in all but one case (4 cases total) was paid directly to the school by the bank.
-I made almost 17k this year (combined student job income and new job income), which is significantly more than I made any year of college (I think the most I made any year of college was about 4k). I realize this may effect the amount of this credit, but I’m under the impression that I’m still eligible for some part of this credit.

So basically the question is, how do I go about going back and retroactively fixing those tax filings, so that I can get the additional refund I think I probably should’ve been getting?