J.P.
I strongly recommend a female Boston Terrier. Female dogs are more docile than males and the Boston is a small, sturdy, intelligent (easy to train), playful, loyal dog. We have a 10 month old and our Boston is excellent with her, even if she inadvertently pulls the dog's ears! The dog was very easy to train because Bostons are very loyal to their owners and want to please them so badly that they will do anything. I even taught our dog to catch frisbees and I'm no dog trainer. A breeder is the best place to get a new dog, but in your case I think a dog that is already housebroken would be best. Dogs in the midwest that are available for adoption are listed at http://www.midwestbtrescue.org/
Good luck!