need help with Receiver setup

[beyondHighDef]

hey everyone

sorry if i posted this in the wrong section.

Anyways ill get to the problem with the receiver (if i can call it that)
my main receiver is a sound card on my PC - its my main and only receiver.
The problem is that it does NOT decode Dolby Digital. The card is this:
http://us.creative.com/products/prod...&product=16770

I have my Playstation 3 over HDMI connected over DVI to my PC monitor
but no audio over HDMI so I went for optical.

The optical cable goes to my PC. the receiver card cannot decode DD.
my question is: if my sound card cannot decode Dolby Digital from S/PDIF input, can I somehow decode it with software so I get sound over my PC speakers?
I was looking online for a while, i found no software that can help me. I looked at a ton of software programs, etc and i didnt find the solution

(I guess theres always Plan B - Buying a new card with S/PDIF input that decodes DD)

once again sorry if this is posted in the wrong section. and thanks in advance.