PS3 and 7.1 Self-Powered Speakers

[Great Hierophant]

I have a new PS3 Slim and this is my first entry into the HD world. I also have a 1080p TV and a set of 7.1 computer speakers. What I want to do is to find the cheapest way to connect these speakers to the PS3 and enjoy 7.1 non-downgraded audio output. This includes Dolby TrueHD and DTS HD-MA in 7.1.

My speakers are the Creative Gigaworks S750. The satellites are powered through the subwoofer and ideally are designed to be connected to a PC sound card with unamplified line outputs. My TV is an 42" RCA model L42FHD37.

I know the PS3 can decode both TrueHD and MA-HD into linear PCM or bitstream it to an AV receiver that supports decoding these formats. Obviously I am trying to avoid the need to bitstream unless decoding via linear PCM will degrade the audio quality.

I need a device that will take the HDMI input from the PS3 and output the video via an HDMI out to my TV and make the audio available to my speakers. Does such a device exist? If not, what is the cheapest receiver that I can buy that can handle this?