In short if you haven't got the papers to prove otherwise you've got a mongral. It could be that she's purebred but if her parent isn't a pedigree kc reg bitch then it doesn't matter what she looks like.
Another point is that only the breeder of the pup can register the pup with the kc so having the details wouldn't help you anyway :(
My final point is... SHE'S TOO YOUNG! Even if she was a kc reg ped staff you wouldn't be doing the right thing by mating such a young bitch :(
I hate to harp on but it is irresponsable people mating staffs for profit that is weakening this great breed and giving it a bad name as being owned by idiots

She couldn't possibly be a show winner as she's not yet registered so why do you want to put her through this life risking process, if not to make a few £££'s? Just look in your local paper and see how many others are doing the same thing :(
Please, please don't breed from her.