Help at Wits End

Does anyone have any advice on how to treat this? I have been fighting it for almost 6 months now. It started as a small patch on her udder and has now spread to her ears. Our local vet admits that he doesnt know alot about goats and said it is a fungus and gave me some anti fungal pills and I gave them to her for four months, it would clear up but as soon as I stopped the medication it came back the medicine cost me 2.00 a day to give her. I am terrified my other goats are going to end up with it. Another vet I just found recommended iodine baths and I have done that and also to try Listerine. I am up to trying anything now just to get rid of it. She is bred so I am limited on what to give her and not hurt her babies.
Please help, I feel like such a horrible goat mom for not being able to help her. She doesnt seem to be in pain, when I touch it she lets me if she is eating.
Thanks
Rasha