Been there before and unless you are okay with the quality of sound, even a high quality AVR offers, then you might consider going the home theatre bypass route.
That way you can use the front left and right speakers for both HT and two channel.
Only requirements are that the preamp or integrated amp will need to have the HT Bypass option and the AVR will need to be able to "preout" the left and right fronts independently.
There is plenty of information available online and there are a multitude of amplifiers that offer HT bypass functionality.