+ There are websites to advertise your stud...KIJIJI is one of them. You can use newspapers also. The best thing to do is join a Boston Terrier Club in your area. You can google that. If your pup is registered with AKC join that one or use whatever registry you have. There might also be a "Meetup" group in your area. Houston, Texas has one called the Houston Boston Terrier Meetup Group.
http://www.meetup.com/bostonterrier-74/
You can post messages there too.
Check out any ads that are looking for a stud. Just be sure to demand that the female be seen by a vet immediately prior to any breeding. Make sure she is registered and meet the dog and owners beforehand. Be sure the female does not have any inheritable traits that are undesirable.