I have a dog training question?

I have a young dog, mix between a chiwawa and maltese (older than a pup) that has never been properly housebroken. He is actually fairly obedient otherwise, and I have tried everthing i know, including set times for feedings, long walks etc. Should I go get a book on Dog training or should I pay a service to do it? If I should read a book, can you name some good ones? If I should pay a service, what would be reasonable? 1 session? 3 sessions or longer? what would be a resonable rate for simple but effective housebreaking training. signed, up to my nose in dog poop/pee!