Expose them to one another gradually under controlled conditions. You want to avoid creating situations where the cat runs away and the dog's prey-chase instinct is activated.
After the dog has explored the new house, it's probably best to confine the dog to a room (with some one in it with him) and let the cat smell where the dog has been in the house, under the door, etc. Also, pet the dog and let the dog lick your hand - then let the cat smell your hand. And vice versa. Don't worry...Your cat will probably end up beating up your new dog...lol
BEWARE...THIS COULD HAPPEN!!!!