Okay, so i am pretty sure that i am getting a macbook this weekand and i am still a little confused on wireless internet. i know how to set up the router and everything but our home only has one computer so will the PC and my macbook both be able to go on the internet at the same time even if they share the same cable modem? and does wirless internet cost extra (we only have cable) or does the router just send a connection out?? please help!!