My dog won't be potty trained. Barks constantly. Read Details. Please Help!?

Hi, my dog is a Cavalier King Charles. He's four years old and was the runt of the litter and not the smartest of the bunch, although very loved. When we first got him we kept him in a crate per instructions and consistently tried to train him to stop barking and whimpering as well as potty train him. He has done neither no matter what we do or how hard we try. He has not been neutered because we were thinking of breeding him. He doesn't get walked very much because we are a busy family and live in a very hilly hard to walk area. We let him out in our yard many times a day. He is confined to about two rooms in the house now because we can't let him roam or he will pee. He pees outside but then once he is inside he will immediately pee again. We are not sure what to do, were thinking about either giving him back to the breeder or neutering him to see if it helps if this doesn't get resolved soon. Please give any advice, it's much appreciated.