Does your TV have any form of audio output that is compatible with any audio input on the AV amp?
If so then simply run an appropriate cable between the two and use the AV amp for all audio duties.
If you are unsure post the make and models of both TV and AV amp and I'm sure someone will know what the options are.
And if you do use a separate media player with HDMI and HDMI inputs on the AV amp then the amp will suck the audio data out of the HDMI feed and deal with that itself and send the remaining pictures onto the TV.
Yes, the TV has optical out, but isn't that inferior over HDMI? For example, would I get dts over the optical lead?