Buy a crate and a baby gate. Crate training is the most efficient way to housebreak your dog.
Dogs are canines and canines are den animals.
Their new crate will be their den in which they will sleep or be confined when you are not able to supervise them every second. Crates should be their security and their bed. It should never be used as a punishment. Dogs are naturally clean animals and do not like to soil their sleeping quarters. A crate should be large enough for the dog to stand up and turn around.