Hi Mr Woollie,
A trip to your local Hi-Fi shop will sort you out. What you are looking for is a Male stereo plug with two wires hanging off it, one with a red jack, and one with a white.
http://www.starland.co.uk/pages/kia/a43.htm
Scroll down to the KL400/1/2, to see a picture, as I can't work out how to post them..
As you can see they start at a couple of quid, so it won't bankrupt you.
Cheers
Liam