Bankroll/New comp

[JosephAnthony]

I recently started playing poker online on my parent's comp. I have raised my modest 150 dollar investment to 600 dollars playing on party and stars. However, i leave to college this fall and cannot take my trusty old comp with me, only my Mac laptop, and i don't even want to involve my Mac with poker, b/c i like to multi-table.

Anyways, i need to buy a PC in about 6 weeks. Assuming my bankroll continues on its current trend it will reach 900 or so by then. I have plenty of other "real" money in a separate account, but how much of my bankroll should i diphon off to keep playing 2/4$? should i consider dropping in limits temporarily?

I know by now you die-hards are getting mad at me for posting this in Comp/tech, but my more pressing question is: what PC should i get? How much more expensive would a laptop be than a desktop, assuming the system is capable of handling 4-tabling? also, what should the groundrules be for my system performance? ALso, is the dell the way to go?

Thanks in advance, and btw, i did see the post before me, but my question is slightly different. I prefer laptop poker but wouldnt mind sacrificing the space to a desktop if a laptop would be too expensive.
Edit:
BTW: Keep in mind that this desktop or laptop would be for poker only, not gaming. would that reduce necessary specs?

Also, what about internet connectivity? I will be in a dorm. Would an airport wireless card be a bad idea? I heard connections can cut out on you momentarily. Would a hard cable as the rule be the right way to go?