hey man
if you buy a laptop with built in wireless networking, then you won't need to buy the a networking card, as you will already have one built in.....
all you would need to link it up to the internet is a wireless router and you should be laughing....
with the wireless router, you can plug your exisiting pc into the back of it using a network cable, and connect your new laptop to the router using the built in wireless networking.....
this is assuming that you have some kind of broadband internet - if you are dialing up from your pc, then that is gonna be a different matter......
Cheers
Jonni