If you want something, go out and grab it... Is this guy one of your good friends or just a friend you see once in a while? and to me honestly man... it just kinda sounds like your just her orbiter, she comes to you when she needs advice, that means she trusts you like a brother not like a boyfriend. Have you even madeout with her yet? cause that would be the first step in finding out if she actually likes you. A lot of girls play sick games with guys and I've seen it happen so many times.
You might wanna just sit this one out and find a new girl, shes sounds like your one-itis if you've been waiting around for her to break up with her boyfriend.