Where can i buy a 4 pin s video to male RGB component caable?

I bought a video capture card recently which has an s video and standard Y rca hookup on it. my cable dvr box only has the component RGB and audio RW and regular rca Y video. I am looking to get the best quality from my dvr and would like to find a 4 pin s video to male component cable to make it work.|||Check out meritline.com They have tons of specialty cables, and great prices too.