hello to all pros,

i have an inquiry

im using HDMI as my video output to my lcd tv, but for audio, i wish to play 5.1 surround ...
so my options are either get a surround amplifier + speaker (which is bloody expensive) ...as alternative, i was thinking whether i can use computer 5.1 speaker (altec,creative..etc) to play surround sound system?

and my other concern is, is there any computer speaker comes with multiple chanel? like i wanna switch between PS3 and my computer.

i understnad my problem can b resolved by getting an amplifier, but it'll cost me a lot


sorry, if my questions sounded dumb and unclear ><... just need a piece of advise here.