Just get a modest DAC with optical input. It will almost certainly equal and probably better the DAC in any low-cost AV receiver you'd get, then you can just use your existing preamp and amp. Toslink's shortcomings are greatly exaggerated. Use a glass cable if you can -- e.g., Wireworld.
BTW, where does your TV content come from -- is it all OTA?
BTW, where does your TV content come from -- is it all OTA?