Gosh, I remember those flirting days! I still flirt sometimes, despite being married. Its fun, what can I say. I'd flirt with her, she has a boyfriend, SO WHAT! If she doesn't have a ring on that finger she is fair game. Ask her out, be persistent and be a good friend. Don't get pissed if you get rejected, but be someone she can confide in and come to. If things go wrong with the current boyfriend you will be a great shoulder to cry on. Good luck!!!!