You can purchase a new key fob for a few dollars on ebay. The only thing I might try to fix on one of my key fob is to replace the battery. If the unit was still bad after that, I would throw it away and buy a new key fob.
It is easiest just to get the key remote replaced and reprogrammed because it is relatively difficult and expensive to fix a broken one. I would recommend looking on ebay for a new one.
