Well first off, her ego is a big problem. It's gonna take a shit load before she even contemplates changing. Trust me. If you ever tried changing yourself, you'll know how hard it is. Let alone trying to change someone else? With an inflated ego to boot? Like what silverstar has said, pick yourself up, dust it off and just keep walking.
Get on with your life. Btw, don't literally force yourself to be happy. It is also unnecessary to put on a false happy face. By all means, if you feel sad, let it out. HELL let it all out. Purge your soul of the hurt. Cry, shout (into a pillow) whatever.. For this brief period, give yourself the FREEDOM of expressing/properly grieving your loss. Talk to your friends/family if you have to. Though, don't drive them crazy repeating your problems again and again.
After this, close the chapter. Go out there, live your life and be happy. Think of the things that you've always wanted to do but couldn't do when you're in a relationship. Excited yet?
Continue on, and before you know it, hey, you're really over her. By this time, you'll probably not even want her back.
However, I do stress that rebounds, in my opinion, is a selfish act and is BAD for your health and the person that you rebounded to. In my opinion, rebounding is for the weak. It is a distraction. I would go the 'harder' way by healing SINGLE. I know some people would attack me on this point here but this is purely my stand. Agree to disagree if you feel otherwise.
Don't be worried about that empty space in your soul. Truth is, that hole there.. It is NOT the shape of your EX. It is the SHAPE of a WOMAN. In time, it WILL be filled. Maybe even with a better woman. Stay positive
