windows xp to 7

i, of course, need to upgrade to windows 7 from xp. Being a idiot I have a few questions. I have to save all my folders and programs before I make the change... so I have to save Norton Internet Security too? Can it transfer to the new windows? How much protection will NIS do until I make the change? Don't trust NIS for a second once XP support ends? And.... If I buy the cd for windows 7 can I put it on my 3 puters for that one price of 100 some bucks? I just heard about xp ending a few days ago and it is NOT good!!!!