Help with surround sound

Im hoping theres some hi-fi experts out there that can help me with this.

I have some logitech 5.1 speakers, they come with an adapter for game consoles but that only has output for left and right speakers. So i have sound out of all speakers but only left and right sound (did that make sense?). I was wondering if it is possible to get audio through a HDMI or an optical cable to play in surround sound through the speakers i have? Does anyone know? or even have a link to some help would be great.

I was going to put a picture up of the adapter and audio jacks my speakers had but photobucket wasn't working.

If you want a picture or something needs explaining just ask because i really want to get this working

http://www.logitech.com/index.cfm/speakers_audio/home_pc_speakers/devices/211&cl=au,en

it has three 3.5mm jacks in it, green, black and brown.

thanks for replying  

I have the same problem with the z-5300e, as it only uses analog signals. I doubt yours has digital connections. The only possible way is to use a Creative DDTS-100, as it converts from the analog to digital and vice versa on the fly. However it is discontinued and incredibly hard to find (EBAY racks up to about $300). The new Logitech z-500 has an optical in connection to e with digital technology.

If you're buying a sound system for the PS3, you'll want a 7.1 system, not a 5.1 system.teebeenz