Tell me about this condition (Dog Knowledgeable is helpful)

So, I have a dog, and she is about a year or so old. A few months or so after we got her (We've had her since she was about 7 weeks), she started to develop an ear condition, which progressively got worse.

We took her to the vet, and they said she had a Chronic Ear Infection, caused by either the food, or it was Seasonal, but that it was impossible to really tell just by looking. She prescribed some medicine which helped, and we did our best to change any factors that might contribute to it (at the time, the food).

It got better, but when we ran out of medicine, it returned a couple weeks later (although to a lesser extent). We've been trying various foods, especially ones with Low Wheat (as it was suggested that wheat could be the cause), and its now Winter (when it was Spring), and its definitely not any better. We've tried eliminating the Seasonal thing, and the food, but there must be something we're missing.

We're going to be taking her to the vet when we can, but in the mean time, I'm just wondering if anyone has suggestions that we have yet to try that might help her until we can get her seen. Its to the point where she is scratching her ear until it bleeds. I've been doing my best to stop her from it, but when we're all asleep, she'll do it anyway.

Just for reference sake, here is a picture so you can see what it looks like at the moment (taken just a few mins ago):

http://img130.imageshack.us/img130/1410/700px.th.jpg