Have them meet somewhere other than at your house. Give your dog plenty of attention, especially for interacting appropriately with the pup. Take the pup home with you and pop it in to a crate and give your dog more attention. Let them get to know each other more with one or the other in a crate, then start taling them out to go potty together. Always give the old dog more attention and treat for interacting with the pup in an appropriate manner. Pretty soon older dog will be showing pup the ropes.
