
Sorry to hear about your loss but he was a good age. Try this website and there is a contact e.mail for the secretary who should have a puppy list http://www.bordercollieclub.com
It is important these days to make sure your pup comes from hipscored and eye tested parents. The pups should be tested by the breeder at around 6-7 weeks of age also.
Good luck, come back and tell us when you find one.
Sandra