Creating a home theater..

Alright So I Just bought a 1080p projector and screen for $200 at a garage sale. I Am looking to create a home theater with one of my macs, I Am usually good at doing this, but I'm lost. I Cant figure out how to be able to use my blu-ray player, along with my iMac 21.5 inch (2010) or with a Powermac G5, It seems like the powermac would be a better choice with its optical audio, but My AV Receiver blew, So I Am trying to use my iMac, or Powermac, as the AV Receiver, Currently I Setup My Audio Setup with an 3.5mm audio splitter thats plugged into the iMac, 1 output going to my Energy subwoofer, and the other output going to A 2.1 Logitech sound system across the room, and That has an additional output, going to another 2.0 sound system giving me in theory a 4.2 sound system setup to it, it sounds phenomenal, and the video is going from a mini dp, to dvi adapter, through dvi, to the Projector, onto the projection screen. I Would use HDMI, but i have no Mini DP to HDMI. Not sure if it would look better anyway. So I Have the video and the audio situation figured out, but I Am stuck playing dvd's on the superdrive, I'd like to use blu-ray, is there anyway to hook up a blu-ray player (not drive) and use it on the mac? thanks