Excellent advice above!
Might I also recommend the advice of a professional.
http://www.dogtrainingnh.com/
She will come to your home and help train you and your pooch.
I could not for the life of me get my young pup from wanting to chase cars while walking her. It was real bad! I tried everything I knew and could think of but the problem just got worse.
In one session of training my wife and I, the problem was solved.
While I have trained many dogs previous to our current, I am not a professional and wasn't about to chance the life of my dog for my ego, that is why I called in Ryan. She was literally a lifesaver for us and our recent pup! Can't say enough good about her.
Good luck!
Dan