Okay, the full version has been uploaded and should show up on the site soon.
k: It's over 2 MB, so you should be able to tell from the game's page when it gets updated.
Ignore the prompt to insert Disk 2 during the installation and just hit a key.
Each episode is its own program, so you need to run TD1.EXE, TD2.EXE or TD3.EXE to get the episode you want.
Finally, if you want to keep your saved games from the shareware episode instead of starting over, keep a copy of your current TD.SAV file and put it into the registered games' directory after the install.