My finch is having ear problems.

My zebra finches ear is all red inside and there are feathers missing around it. In a book I read it says that you can use medical supplies such as antibiotic ointment or hydrogen peroxide. What one can I apply to the ear to help it? I can't afford the price for an avian vet..and when I call they say there is nothing they can do unless I bring her in. What can I use to help the ear??