When I want to separate the tank from the upper half I put a piece of rubber around the upper right where it joins the tanks an place it in the vice upside down. Then spin the tank off. Every once in awhile I have to but a rubber strap clamp (like you use to spin off an oil filter) and help break it loose. Make sure the rubber strap is on the very bottonm of the tank or you will dent it when pressure is applied.
This place has the Sears Decals.... http://www.oldcolemanparts.com/home.php