Don't approach her like you would at a bar.
If you roll up on her and lay down a pick up line, you'll instantly be that creepy dude at the party. After you leave, she'll ask who brought you, shaking her head in silent disapproval. So, maybe think twice before asking if she can be your "tight end," or making any straightforward, aggressive moves.
You're at a party with mutual friends counted in present company. Take advantage of the relaxed atmosphere, don't work against it. You have four quarters, many commercial breaks, and a halftime show to have casual conversation with her and be your witty self. Be subtle. After all, you can always just ask your mutual friend(s) to bring her around more often. It's all about the slow build, gentleman.