To upgrade intergrated amp

In order to extend the function of my NAD intergrated amp., would there be any way to make it upgrade to 5.1 ch for home theatre. (Since I am goning to buy a new one,but feel wasteful to discard the old)
Which model NAD?
Wait till you get your 5.1 set up.then compare;Your int.may sound better on 2 ch music.