A girl I truly love, I want her back... Please help me?

There is a girl I truly love, and we were best friends for a long time. Then she finally asked me out after she broke up with her ex. Our first "date" was at a mall, we had dinner, and played in the arcade, and had a wonderful time. When we went back to the car, we cuddled for a long time, and she just kept trying to help me "get some guts" to kiss her. I was shaking a lot, since she was my first girl, and when I kissed her, it was like magic. And on top of that she bit my neck, and I mean OW! Then, after being so high from the kiss, I bit her back when I got home, and she loved it. But the next day, she became unsure of our relationship, apparently she didn't feel a "spark" when we kissed. Then a few days later, we went to see a movie, and we cuddled through the whole thing. She even admitted she wanted to have sex, and she has done it before, but I haven't, so we didn't. We both had a great time at the movie, but the next day she was unsure again, and kept mentioning another guy. One day things would be fine, the next day she had doubts. One night we poured our hearts out to each other and cried, and she actually told me she loves me, and I said it back. After that when we hung up I dropped the phone and collapsed crying. Then, she told me she needed time to think, and at the end of that weekend, she was going out with the guy she was talking about, saying he is a dream come true and knows more about her than she does herself. And I'm truly happy for her, but I know I love her more than he ever will. I would die for her. She played head games with me for a week, after that kiss, and then she leaves me for him. Every time someone would ask if we were dating she would say "kind of," because she didnt want to broadast it. I want her back so bad, just a chance to prove I'd do more for her than any guy would. She's got me listening to music I never would have listened to, like Conway Twitty, Journey, AND I"M A ROCK N ROLL MAN! Iv'e been listening to Every Rose has its Thorn by Poison, and Patience by Guns N Roses, because I want her so bad, and I express it through music. We are still friends, but I love her too much to let her go, but she apparently loves me, but isnt IN love with me. That damn spark thing she kept mentioning is getting to me. I don't know if this will help, but to some people it seems important. She's an aquarius and I am a Libra. I'm a calm cool and relaxed guy, but she is what she likes to call a "party girl." I want her more than anything in the world, and I want her back more than anything in the world. What in the world can I do, and should I do, if I want her back, and love her, to prove it, and to have her heart. I believe in hope and willpower, and thats all I need in a relationship with her, as long as we love each other, we can work. I'm "Mr. Brightside," just like the song, I get attached fast and, well, use google to look up the lyric meaning, at lyric interpertations or something. I need her, I love her, even though she hurt me, I still believe we can work. What can I do? Please help this "great guy" who is in love and can't let her go.