What kind of dog do you have, as some dogs are anatomically prone to ear infections, such as retrievers and spaniels. Do you know what type of infection it is (mites, bacteria, yeast) - has a vet treated it before and if so, what have you already tried?
You can treat symptoms and/or the cause. It is possible to be food allergy or hypothyroidism related. What type of food are you feeding? It is always best if you feed a natural raw food diet as this will boost the immune system.
Natural treatments could be using aloe vera gel which is applied topically. Calendula is a healing herb that can be applied topically, but do not use if the dog is pregnant. You could try Colloidal Silver topically. Or mild hydrogen peroxide solution topically.