How To: Set Up MacBook Pro, Traktor Kontrol S4 and MPK Mini

I have been having trouble with my audio output through Traktor using my S4, MBP and MPK Mini. What I want to do is set up my audio to output through my MBP's speakers for now. I have not yet acquired monitors and would like to be able to play through my MBP's speakers as monitors using the S4. When I use just my computer it works just fine, but when I plug up the Traktor it outputs only through my cue. I think the problem I am running into is that when the S4 is hooked up its using the S4 sound card as the primary card. Is there any way to get it outputting through my laptop speakers while using the S4 and Mini to control the interface? Hoping I dont have to get monitors just yet, I'm still paying off my S4. Thanks in advance!