I really like this girl?

I was unsure about it before. when i met her i totally got an "i like you vibe" from her. I was looking at the situation like "yea maybe ill give her the privelage of going out with me" but then i found out she had a (long distance) boyfriend already, and suddenly i got so jealous, and also confused by how nice and nervous she acts around me, and now i cant stop thinking about her-- wtf gives?! moreover what do i do about it? lately we hang out a lot. the other day, i --perhaps all too boldly-- told her that i think her friends are boring, and to my surprise she was just relieved that i felt the same way she did! we definitely connect really well...the problem is just that she openly talks to me about her boyfriend, and because i didnt immediatly make a big deal about it i guess she got the impression that i just want to be her friend. i told her about this movie i got and told her we should watch it, and she agreed. but when it's just the two of us i really don't knwo how i should act. If she wants to hang out with me one on one does that mean she is interested? i obviously was misreading her signals before so i can't rely on that, and I definitely can't just make a physical move... what did i do wrong? more importantly what can i do NOW to start fixing it? I'm afraid if i am too platonic when its 1 on 1 that ill blow my chances for good!