If you weren't given the official registration forms for your dog when you got it, you'll need to go back to the breeder and find out where they are.  The breeder has to register the litter in order for the pups to be eligible for registration. If you weren't given the papers when you got the pup, chances are the parents weren't registered, and so there is no way of proving the purebred lineage and registering the dog as a pure breed.

 If you go back to the breeder they should have them and then in with the documents you will have like a family tree regarding the dogs family history