Install 360 on two new computers. Still have a year to go on our old subscriptions

Just purchased two new laptops (Win 8) and need to transfer our subscription with one year left on our old computers to the new computers.  Purchased the old program from a store in 2010 and the program was registered and installed on both computers.  It was good on up to 3 computers.  I extended the subscription for 2 years in 2011.  What do I need to download and what do I do to transfer the subscriptions?