Hi sbooner02
Welcome to the forum.
If you have the SS2006 add-on you can download a SS2008 version of those ships for free. Read more about this, here:
http://www.shipsim.com/ShipSimForum/index.php/topic,3052.0.html#new
Installing patch 1.1 adds jetski and hovercraft to your SS2008. Patches can be found here:
http://www.shipsim.com/downloads/patches.php
It isn't possible to add the ships from the original SS2006.
Regards
groennegaard