Yamaha DTXpress/DTXplorer/DTXtreme

Hey,
I'll start with the obvious - I'm a drummer and for christmas I got 
a Yamaha DTXpress II. I love the machine!
Anyway, I also play and compose a lot of music, as I play other 
instruments as well.
I'm hoping to get a laptop very soon, on which I'll be doing a lot 
of music composing (using something similar to Cubase or Cakewalk 
hopefully), but unfortunately, I have no idea how I'd go about 
connecting my DTXpress II to my computer/soundcard and using it for 
drums in tracks I'd write (presumably MIDI?). I know I really should 
know about this, but I'm afraid I don't! Any help would be very 
greatly appreciated.
Also, since I'd be using a laptop for my music creation, I presume 
I'd need to buy a new soundcard, as laptop soundcards are 
notoriously poor? What are my options here? Any recommendations? 
Would it have to be an external card?
Thank you in advance for any help anyone can offer,
Ferdie
PS Please talk as simply as possible to me, I understand little or 
no technical jargon! Thanks.