I am by no means an expert, but I would imagine calcium and vitamin D would be a good place to start. My mother always tells me that weight-bearing exercise can help build bone in general, although with a broken bone I've always heard that movement is bad so I guess I wouldn't lift weights, at least not with that foot/leg, until things are healed.
I hope you heal up soon, Helen! No more stomping around, no matter how naughty your dog is!