DUDE!
You sounds like she's the one gaming you, she's got it all you buy her stuff treat her like she's a princess and she gets to firt with any man she wants. To be honest I'm not liking the sound of this girl - but lets asume that she is nice...
How long to you freese her out for?
Option 1.
Use her as social proof to show other women that you have value and then hit on them. This will of course bring her running to you. Be strong young jedi, or at least make her work REALLY hard for it
Option 2.
Call on her it... say "you only like having me around cos I do stuff for you, now I can see that I can see what a manipulating bitch you are and that you never had any intention of really liking me." Seems harsh but and she will be hurt, but you have the golden-get-out-of-jail-card. She will probably go f*cking nuts at you. Be strong and just say "well I never imagined you were such a bitch" look at her like you are going to kiss her and do the whole slow-down smooth out about to kiss you thing.
At this stage you've got her trapped and she will have to kiss you to regain her self esteme.
This takes some balls to do - but it will work. If you know about Maslow's Hierachy of needs.
http://en.wikipedia.org/wiki/Maslow%27s ... y_of_needs
If you knock someone down a level they will want to get back to the level they were before.
Option 3.
Forget her.
Option 4.
Carry on being a chump and feel the pain as this other guy takes her out and sleeps with her.
If I was you Option 1. Seems like the path the happiness.