Reply to XONE:4D & Traktor HELP!

I have been playing around with two cdj-400's, a djm-400, serato sl1, and my macbook pro for a while now but I want to get into something a little more digital (don't see the point much of having cdj's when i'm using serato)...

so i picked up a xone:4d and traktor pro.

My question is do I need anything else other than a 4d and traktor? Can I control traktor from the 4d and have the sound come out of my mixer, or do i need a separate external soundcard like an AUDIO4DJ? or do i need a traktor scratch external interface? or soemthing else?

(if I don't need one of those options, would i be expecting sound out of my mixer or out of my macbooks headphone jack???) (and how the hell do i set this up in traktor!??! haha)

thanks in advance