Depends on you. How much do you really love her? If you believe she is the "one" for you (at least for now), then stay single just for her. She'll notice and she'll get touched that you'd do that for her. The next part would depend on her relationship with her boyfriend. I might be reading the situation wrong, but I think that they're beginning to drift apart. If that's so, then give it a couple of months at most and she'll be single too. At that time, you know what to do already. But if I'm wrong and she just thinks of you as a friend, then best to do is just to move on.
Good luck!
P.S - don't be too impatient. The best things in life are well worth waiting for.