I still think she should go to the vet and make sure it actually IS ear mites. I would hate for her to treat for ear mites, and it actually be a yeast infection. That would only cause the pup to suffer longer than necessary. When I suspected Lexi had ear mites, I almost bought some over the counter medicine to treat it, but I'm glad I didn't since I was wrong about the diagnosis.
Here is an article I found.
Ear Mites or Infection? | Sit and Stay