Don’t go to shelter or RSPCA because they do put them down. There are usually volunteer organisations, or even private citizens, some of whom your local shelter might know and be able to put you in touch with, who take in stray and try to find homes for them. A community search would help you find them; try libraries, local pet shops, vets, etc. Good luck. It is great to see someone who cares; I hope you can find a home for the poor little dog.