Dude... reading your post is like looking into a mirror. My ex ignored me for the last two months while dating some other guy. We used to get on very well, and just yesterday she called me up wanting to hang out. She apologized for ignoring me, but at the same time she's just been dumped by that guy! So tonight it's either drinks and a comedian with her and some mutual friends, or hopefully my brother's fraternity party.
I don't know if i want to tell her to bugger off or give her a chance to be my friend. Either way, I'm moving 4500 miles away from her in a month so I don't think it matters much for me. I've given her enough chances already, and if she's not sincerely sorry she's not getting another one. I already forgave her for losing her virginity to another guy while we were still off and on, which, come to think of it, I probably shouldn't have done! Man, now i'm angry. I think I'm just going to politely say that there's no trust and we can't be friends since she clearly doesn't care about me. Therefore, my advice would be the same to you.
Good luck!