How do I fix the roller on my Dyson DC25?

I know why the roller on my Dyson stopped turning. It stopped because a small black plastic piece that connects the roller to the Dyson and acts like a "for lack of a better discription" bicycle chain in that it turns the roller, has broken. I can't seem to find a place locally where I can get this part. Is Dyson the only place where I can get replacement parts to fix the machine myself?