There are plenty of great resources out there for you:
www.pdsa.org.uk
www.humanesociety.org
dogtime.com

What Does a Puppy Farm REALLY Look Like? Could YOU tell?
Puppies bought from puppy farms are more likely to develop illnesses and have long-term problems with their behaviour later in life.
How to find a responsible dog breeder
If you've checked shelters and rescue groups and still haven't found the right one, here's how to find a responsible dog breeder.

Finding a good dog breeder - DogTime
Unlike pet stores and unscrupulous breeders, good breeders are careful to breed only healthy dogs with good temperaments.