I don't have any personal experience with ringworm, but there have been a number of people here who have helped rescue dogs with it. They will be able to share their knowledge and experience.
I googled and found that like fleas, cleaning your home is vital in combating the ringworm:
"Use bleach mixed at 1:10 on any surface that you can. It will kill 80% of the spores. Vacuum on a daily basis a dispose of vacuum bags which will contain the spores. Steam cleaning of carpets and furnishings will also kill a large number of the spores.
Don't forget your dogs bedding and kennel. Wash the kennel down with a bleach solution and wash the bedding in very hot water. If your dog is an inside dog confine him to one room of the house."