Reply to Laptop to DJM 800

Hey everyone, a group of friends loves to go karaoke every now and then... but it can get pricey with all the private rooms we go to (Korean style). I looked online for a few cheaper solutions since I already own a PA system and mic. I found this software, Karafun, that allows me to play any song on their server for a two day fee on my laptop. Very nice and convenient for us.

So here's the question. I have a DJM 800 that allows me to hook up my PAs and mic. How am I able to use the PA speakers that's hooked up to my DJM 800 to play the sounds from my laptop?

Thanks guys!