5.1 Sound Card and 5.1 Home Cinema System Problem ?

Hi,
I have the following Problem, My computer has a 5.1 sound Card which has 6 plugs (3 Outputs and 2 inputs) (Mic-In, Front Out, Center/Subwoofer Out,Souround out, Line-in, GamePort) and I have a home Cinema 5.1 sound system which was plugged into an old DVD-Player I have through 3 RCA Red-White 2-2 Cable , The Problem is that the DVD Player had 6 entries ( 2xFront Out, 2xCenter/Subwoofer Out,2xSouround out) And my 5.1 sound card has only three for the 5.1 System and 2 other for the mic and line in . Are there Special 2-to-1 RCA Cables in the market that enable me to plug the 5.1 System to my computer without loosing Quality ? if this possibility exists , will it function normally ? Do you have suggestions?

Thanx

need cables? check this site for good selection and prices http://www.monoprice.com/home/index.asp I think what you are looking for is a 3.5mm stereo plug to dual RCA