Hi,
Go to Planet Auran on top of this page. There you should have a choice Legacy Order History to the left (assuming you are logged in). That will bring up a list of your purchases. Click the one for TS12, and there you have the download files.
After installing, copy the folders UserData/local and UserData/original from the TS12 installation directory of your old computer. Then do an Extended Database Repair, and that should be it.