Reply to Digital Vinyl setup HELP??????????

I have decided to move to digital vinyl, and I am confused on how I set it up, before I go and buy an external audio interface, I would like some advice, I am currently trying to set up my laptop so that it is plugged into the audio interface and then from that into the mixer and then have my turntables into the mixer, so I can use timecode, now I reckon that part will be easy but I want to have the sound from the software I use 'Virtual DJ' on my laptop to come out of my headphone jack on my laptop so then I can plug my laptop speakers in, until I get a new set of amps etc, now I was believeing of getting the 'numark stereo io' until I have the money for a more professional one, now I reckon if it's possible I could figure it out once I buy the 'stereo io', but I would like someone to perhaps give me instructions of some sort?? It would mean a lot if someone could help me out