The best thing you can do, for your own sake, is to move on and find happiness within yourself. Forget about her. People like that are out there, and they are locked into their own self-destructive self consuming Ourobouric cycles - staying away and not getting pulled into the swirling gravitational eddy as they go down the drain is a good place to start.
Letting go of all the pain and hurt this person has caused you is the best revenge you can possibly have, because as long as you are feeling some kind of emotion towards them you are still allowing their shitty behaviours to affect you. When you can reach a place of true indifference towards them, you will be truly free.