Give the naysayers never no mind, juls... I too, live in the U.S. and I'm glad you've provided a good home... Don't we all have unexpected changes in our lives?
Now, to your problem. Firstly... try to determine that it's actually mites you're dealing with. I live in the intermountain area of western U.S. and have working dogs here on the ranch that we home-treat very successfully for some time. Take a piece of tissue paper, Kleenex type stuff and wipe as deeply into the ear as the dog will let you. Place the tissue in a bright light and watch it for a little bit. If some of the residue begins to move and appear to be pinhead size little critters, then you have ear mites. Do you have cats as well? The mites migrate from one animal to the other so other pets should be treated as well.
Next, any topical OTC treatment for fleas will work. You know how sometimes kids get lice infestations at school? The same treatment will work for ear mites. RID is just one of many brand names and it's inexpensive.
Just like the kids and nits, cut the hair around the ear as short as you can. Keep the treatment working for at least ten days, two weeks is even better. The intial treatment will kill the mites but won't do anything for the eggs that will hatch so keeping the treatment up will kill the hatchlings.
Check around the ear opening to see if their are any tiny,whitish nodules clinging to to the hair near the roots... eggs are what you're looking for. If so, comb them out to cut down on the rehatch numbers.
If it turns out to be fungus... well, that's another story... simple solution but try this resoulution first... best of luck!