Can I date my girlfriend's friend if we break up?

I ask this question very seriously, and I am not a person who tries going from girl to girl hooking up or anything like that, but quite the opposite... I started dating my girlfriend in December of my Sophomore year, and now sophomore year has just ended. I originally liked her friend (the same one i like now) but when i found out that my current girlfriend liked me, i became a bit interested. Don't get me wrong, she is very nice and a pretty girl, but i am just definitely more attracted to her friend. just tonight, we were all at another friends party, and i had a great time with this girl we swam with each other until we were the last two in the pool and were constantly laughing and talking (my current girlfriend was inside)... the problem is, the two of them are friends, and getting her to like me could be hard because of that. but there is one more twist.... my girlfriends friend is starting to like this other boy who i know, who is a real jerk. she just started liking him, and he likes her, but they are not "dating" yet. both of the girls are very nice girls who are sincerely nice, and aren't bad kids or anything, but the boy is being sweet to her. what she doesnt know is that he is a kid who fails most of his classes, has gotten suspended from school (iss) multiple times, calls other kids fat and ugly, and, worst of all, came to this girls birthday party on drugs (marijuana). that was the lowest of the low. she didnt realize it, but the other kids at the party did (not to mention that this kid being at her party is like a basketball in a pile of baseballs.. he is a bully at a party with nice people... and its noticable!!) i know im kinda ranting, but i will end by saying that i can't imagine their little romance going on forever, and so when they stop liking each other then i have a better shot.. for now i will continue to talk to her and be flirty and let the time pass... but what can i do to get her to realize what a jerk this other kid is, then move on from my girlfriend to her?? i would never want to be a jerk to my current girlfriend, and i am truly not like that... but i am trying to live life to its fullest and i know i would be happier with the other girl... i know this is a sticky situation that could take a long time to untangle, but can somebody please help me??? thank you!