Download and install Azureus, or BitTornado, or a similar Torrent manager, and then go to MySpleen. There, you will find almost anything you need to download. If you are looking specifically for Dr.Gonzo's set, you will have to go either to www.torrentsearch.us or to www.torrentreactor.net and download the torrents titled "Pre SE LD rip".
Edit: Sorry, I didn't realize you were looking for the supplamental matterial disc... I'm on the same search too