Since your local SPCA seems to be pretty useless, is there some governmental agency, like a county health department, that you could report these people to?
How about a story in the local paper, or a story on the local T.V. news? How about photos on a local website, showing the terrible way they treat their animals? Won't your town or city council take action?
While it's wonderful that you've adopted this kitten, there are still animals living in wretched conditions, and they need someone to speak up for them, since they cannot. It's not right that they continue to suffer. Can you get a group of concerned individuals to help you, as there is power and safety in numbers?
Please do not forget about those you did not take home -- from chickens to cats to large animals. Every day of inaction means another day of suffering for them.