Could use some advice.....

Hi guys, my first post here, this place looks pretty cool though. I currently have a problem with my setup. Heres how it currently lies

Pioneer DJM600
2x SL1200s
1 x CDJ800
1xEKS Xp10, laptop with Traktor

This setup runs an output from the mixer to my Kaos Pad, then to a second PC i use for recording.

All is well but im upgrading my sound card from an Audigy 2 Plat EX, probably to an Asus Xonar. THis card has no Aux ins like my creative box (nor can i seem to find one with any decent inputs), so i need a solution to get sound from my mixer to my PC, some help here greatly appreciated.

I would also like to get a second XP10. My question is, would i need additional hardware to accomplish what i want to do? I can run the two XP10s directly into the mixer, but in regards to traktor, how would i play one track and queue up another? (Forgive me im very new to digital DJing) Ive read places I may need an audio Audio4 DJ or a Final scratch to accomplish this? Im a bit confused.

Incidentally down the line, I would like to add may be a CDJ400 as an aditional midi controller for Traktor, as well as the two XP10s what would be necessary for this?

I hope ive been clear enough, my head is spinning at the moment:) So a little advice would be greatly appreciated:)

Trip