Okay, here's the situation:

A cute girl from one of my classes and I talk every time we see each other. I make her laugh, we talk about the class and how much the professor sucks, etc. Small talk, no big deal, but the point is we get along great.

I got her number not that long ago because she'd mentioned something about studying for an exam, so I went ahead and took the opportunity to get her digits.

So as the exam got closer I texted her and what not...we texted and made plans to study just the two of us (I think a definite IOI). Long story short, plans fell apart but not b/c she wanted them to, but b/c she was in the hospital (kidney stone).

Playing the "nice guy" card, I hook her up with the notes from class and ask her how she's feeling and what not. We talked on the phone, I helped her study, she does great on the test. So she texts me one day and says "hey thxs for your help i owe you big time, maybe food or something". So I play it cool and tell her its no big deal. Was that an IOI or her just being plain nice?

Last thing that happened was this: I text her saying "hey i didnt forget that you owe me one...and how are you feeling btw?" she responds, "thxs im great. and i didnt forget!" so I say, "ok haha you better make it something good." no reply as of yet.

Where do I take it from here? Anything?

You are straight on road for getting LJBF'd - You are just being friendly to her and it seems she is just being friendly to you. Show her that you are more interested in her as a woman and show her why she should be interested in you as a man, and not just another nice guy friend.