piece of cake man. However, you won't get 6.2(WTFTW). you'll either get just 2.1, or it might stretch the sound to all speakers and woofers. 2 channels is still two channels.
All you need is a mini-jack to (R/W)RCA adapter. those can occasionally be had at my local 99cent store, but a gold plated, nitrogen injected, rocket boosted errrr nvm... u might want a cable better than that of the 99cent store's varity though, but taht'll do the trick.
the sound sys wuldnt happen to have a digital in, would it? taht might support 5.1or> surround sound...