When he does go to the vet, ask for the Intranasal Bordetella. It has more effectiveness than the subcutaneous shot. When I worked at a vet clinic, we always used the intranasal vaccine. Remember, as with any vaccine, your dog should be in good health. Your vet will probably give you some antibiotics, then once his cough clears up, you can take him for his vaccines.

Hope he gets better soon