You might find luck at this site...
http://stanleyspring.com/
I know they have a lot of different springs. I'm not too sure if they have the type you're looking for, but I'm betting they do. Good luck, Avis!
Hey Avis...I think you would be able to find what you're looking for at this website. They have a huge range of extension springs, and I've had success before. All the best!
http://stanleyspring.com/