Ok, I’m a lil late to the party, but Let me get my two cents in...
First of al, ya'll were playing with fire (as many have already stated). So you should have expected for something like this to happen sooner or later. Secondly, as many people have also stated, you and her needed to talk more about things before jumping right into the heat of it all.
Now as far as her stating she was completely unaware of what’s going on.... Well, that’s obviously and completely BS... No one gets that drunk, especially when it comes to having sex, i mean c'mon! If she really was that drunk, you had no business leaving her alone in that atmosphere and situation, and even so, it's hard to believe she was that drunk but yet was able to be moaning from getting fucked.... I mean really.... People have a knack of conveniently falling back into that setting and excuse when things happen that they are either embarrassed about or simply want to forget and move on from.
Obviously this incident bothers you, so I would strongly recommend you guys talk about it and deal with it before simply moving on and forgetting about it... or trying to act like it didn’t happen. Things will not get better from here on out if you guys continue this path... Well, that's my two cents... EnjoY!