|You just need an audio cable that you can get from almost any computer/audio shop. It doesn't have a particular name as audio cables come in a wide variety of types.|
You need one with a 3.5mm stereo jack on one end and two RCA plugs on the other. The jack goes into your sound card and the RCA plugs going into the audio input on the TV. There with be Red and White sockets for Left and Right stereo. There will all so be a yellow socket for composite video but you wont need that as you are using S-video.