
Poor dog! I imagine it will take at least 6-8 weeks to heal on its own - as your vet says, the bones are too small to surgically "fix", and if you bandage the foot, the dressing will have to be changed every 2-3 days as it gets so sweaty and yucky otherwise!
I've been through a similar thing with one of my dogs - in August he wrenched a toe, and two days later an infection set in the nailbed. 8 weeks of various antibiotics followed - no luck. He was taken in to have the nail removed - no cure for the infection. So 10 weeks after the original injury he had to go in again and have the toe amputated. Now the hair has grown back it looks reasonable, and I can honestly say it doesn't bother him at all - he can run jest as well as before. His showing days are over though, and he'd qualified for Crufts several years running. Typical!!
Give your dog's toe lots of time to heal - don't rush it, and restrict the free running to help, and with luck she'll end up keeping all her digits!