Will my old receiver work with my new HDTV?

I recently got a 40" Samsung EH6000. While the picture is fantastic, the sound I find to be kinda quiet, especially when I'm viewing HD sources, like Blu-rays or playing games or watching HD channels. I was wondering if using my older Sony surround system would be possible or even worth it? It's a HTIB I got a few years ago that worked perfectly on my SDTV, DVD player, and Xbox but I was wondering if it will also work well with HD upgrades.

It doesn't have any HDMI ports but both it and my HDTV have digital optical ports. One problem though is my Samsung Blu-ray player only has a single HDMI out. Is there some kind of converter than can connect my Blu-ray player's HDMI cable into the coaxial in of my receiver? And the bigger question...would it be worth it? Will the picture from a Blu-ray player and a Xbox360 to the HDTV be degraded at all doing this? And will the surround sound quality be better than what I'm getting from just the HDTV speakers?

I'm sure there's a massive difference in sound quality between DTS and Dolby TrueHD and I would eventually like to upgrade my sound system but this is just a meantime solution to less impressive TV speakers.

Is there such a thing as a HDMI to coaxial adapter so I could hook my Blu-ray player up to the receiver?

It's a Samsung E5400 and only has a single HDMI port and a USB port.

Ah ha...is it really that simple? LOL

Sorry, very new to the audio side of things.

Thanks a bunch! Appreciate all the responses.

Using the splitter, it would be the BD player and console into HDMI inputs, receiver into optical output and TV into HDMI output?

Thanks again!