Dog with mange..help.?

My dog has mange and the mites have infested in her body and because the vet didn't catch it on time it has weakened her immune system, a tick burrowed in her ear and caused severe inflammation and we had an expensive surgery to fix it and now the other ear is swollen and we aren't sure if it's worth it to have surgery because she is so bad. The vet just gave us a medication that is supose to kill it from the inside out. Will her ear ever heal without surgery? We bathed her in medicated shampoo and we cleaned the house to rid it of the bugs. Now our other dog has it..and he is losing fur now too..WE DON't KNOW WHAT TO DO?