Buy a new or different receiver.
I've recently purchased a Sony Bravia 40" LCD HDTV 1080p with 3 HDMI input and one optical audio output. I've connected my cable box to the TV via its HDMI connection. Right now, that's my only device with HDMI output. In the coming months, I plan to purchase a Sony upconverting DVD player DVP-NC800H/B (replacing my older DVD player; I want to still have a five disc unit "dedicated" to playing my old DVDs and CDs) and a PS3. That will take care of the other two HDMI inputs to the TV.
My real issue is in regards to the best audio connections. My Sony receiver is only a few years old, but has no HDMI inputs and only one optical audio input. Right now, I'm currently connecting my DVD player's optical to the one input in the receiver. (The other devices use RCA connections.) However, I'd love to have the optical audio from the cable box -- not to mention eventually hooking up the optical audio output from the PS3 -- to the receiver as well. Doing that with only one input in the receiver is the problem.
So here's the questions:
1) Can I use my TV as a pass-through? Since HDMI is both audio and digital, if I input all three devices by HDMI to my TV, then output the audio signal from the TV's optical to the receiver -- will I be able to listen to all three devices in digital clarity?
2) If so, will I lose any of the decoding for DD 5.1, DTS, etc. -- or for that matter, lose any audio quality?
3) Another option I have for audio is connecting via digital coax. I do have digital coax audio outputs on my current DVD player and cable box; my receiver has one input. How does digital coax compare to optical?
Obviously the easiest solution would be to buy a new receiver, but I won't have the budget for that for a while.
Thanks for any help!