My colleques here says just throw her in a dust bin.
Basically had the same. Now she claims she has another boyfriend, but I take it that it won't last long as (and she said it herself many times) people never really change. So she won't either. What I did was, I gave her a hard time (and I really mean a HARD time) that embarrassed her, made her friends seriously wonder about her and most of all, made her look ridiculous and lose quite a few friends. After that, I was done. I got my revenge and now she can go to hell and the horse she rode in on.
M-G (dumped her sorry *ss in the animal shelter as well)