As far as I know, you'll need a new sound card that supports 5.1 surround. Then you'll have the inputs. My desktop tower has the Audigy 2 ZS Platinum I got for it. It has a sound card and a receiver type insert, with digital and analog inputs/outputs on the front. It was kinda expensive ($200 five years ago). My wife got it for me for Christmas. I've seen sound cards for desktops that support 5.1 surround, for less than $20. I have no idea what's available for a laptop. Check online at MacMall and others, or a local Apple store for info.
1080p Samsung HL61A750 LED DLP / Onkyo TX-SR805 receiver
Oppo BDP-83 / Polk Audio LSi9 fronts / Polk Audio LSiC center
Sony SS-MB100H rears / SVS PC12-NSD / Pioneer PL-514 TT