@bob the brave,
What I am about to say is going to sound very cruel and manipulative, but remember it is for the benefit of the OP.
Now, what you have to do is save your own ego here. She went and **** all over it and left you feeling like a damn joke. You need to take a note out of the other guy's playbook. He may seem like the enemy, but he is not yours. That girl made her own choices and he took advantage of what he saw as a pathetic situation.
You should pretend to be interested and sleep with her. Take some photographs, consentingly, of her naked. Then, tell her she is a stupid hoebag and put her photographs and name on one of those websites full of other sk*nks. It's all the rage right now. This will definitely make you feel like a SIR and teach her to never mess with Bob the Brave, certified badass.