Hi! I've got an old Sony STR-K660P Home Theater and I want to connect it to my PC, I would like to have 5.1 sound but I don't know if it's possible, my PC has only the 3 basic connectors (red blue and green). Do I need a special cable? With like 3 jacks for the computer and 2 RCA for the HT? I've got Realtek HD.