As far as I know...it's time. We have a horse here that's got a badly bruised cracked rib as well and it just takes time. Arnica gel can help with the pain and stimulate blood flow, other than that I'm also open to suggestions.
There is nothing that will help it heal faster. Bones heal as fast as they want to. I would suggest not riding her at all until it is completely healed and only very light groundwork. If it is possible, the best thing would be to turn her out for a couple of months minimum to give it plenty of time to heal completely and not risk re-injury by using her.
i agree with smrobs, as far as I know its just like in humans, all you need is time to let it heal. I would go to your saddlery though and see what they have for pain. They may have a oral med that you could get. But keeping her out of work for atleast a few months is wise. If you work her it could get worse as in dislodge or something. I hope she is feeling better soon :)