Blu-ray newbie questions...

[Yellowjacket]

With the new Sony BDP-S350 out now I was going to move up to Bluray but here's my problem.
My TV is an older 51" Hitachi 1080i projection (I know I know :-( and my receiver is a fairly new but still old by audio standards Onkyo 7.1 surround HT-R520. Neither the TV or the Onkyo are HDMI compliant.
The TV does have a DVI input. Can I hook up the bluray to the tv with a hdmi to dvi cable and run separate cables to the Onkyo for the audio portion? I mostly watch the tv thru the internal speakers and my dvd player thru the surround sound. (I don't need to hear surround sound american idol and friends just my dvd movies.)
The BDP-S350 does internal decoding of all audio EXCEPT True-HD and DTS-MA correct? That it would bitstream and I would need a receiver with HDMI inputs and codecs to get audio output of these sources right??
Should I wait for the BDP-S550? Upgrading the TV, receiver and a Blu-ray player is outta the question. I am just waiting til a CRT tube goes bad in the Hitachi (it is 5 yrs old) to upgrade to a nice flat panel LCD or Plasma (not sure which yet)
Any advice and suggestions please???? I am also budgeting for a new desktop computer ($1100) and Digital SLR lenses so money is kinda tight. (I have to find cheaper hobbies hehe)