Help me out here.
 

Ok there is this girl I like and she knows a little Japanese. Knowing me I know absolutly no Japanese at all. So I was hoping that someone could tell me how to say "Your really beautiful" or "Your really cute" in Japanese.

wow. sorry i can't help im just now studying relationship parts of the japanese language. Try anata wa kawaii.

I'm not one to try this due to it's amazing cheeziness, but monosugoku kawaii! might get you a smile. Even if she knows how cheesy it is, it's bound to get a Japanese-learner to smile, I'm sure. :p

If I was talking to a native speaker (ie. my fiancé), I'd just say kyou mo kawaii ne
which usually goes down okay (it mean's "you look cute today too").