A good electric supply house will have 19 or 24 strand, 24 gauge PVC insulated, bare copper wire. Also Radio Shack is a good source. Just remember to cut to the exact length as the original.

I have done a couple of replacments, but for what it is worth, send it to a good repair shop and have it done. They will range check the receiver for you. Better to spend a couple of dollars now then rebuild later.