Most onboard solutions are fine, so long as you put them to their highest sampling rates, for example the old ALC 889 would deliver it's best results at the highest sampling rate... does depend on how well implemented it is on the motherboard, but you should not have any worries with a modern sound chip... hopefully!
You have optical out, does your receiver have this?
If so there is your answer, you will need to buy an optical cable with measurements that won't restrict you from placing the amp where you want to, as some of these optical leads are very short.
Do that, set up your speakers to the A-B or front speaker terminals, change the audio mode on the receiver to Direct / stereo and you have a 2.0 setup.
AVR receivers are awesome amps for a simple setup like this but produce a tonne of heat and are generally massive.
It was the setup I used before going smaller.
The amp has a Subwoofer pre-out, if you don't want to be experiencing sub 30hz bass, then you can get away with going with cheaper home audio subwoofers.
It will need to be active and have it's own amplifier.