As most CD:s where released in the 90ies, they may now be hard to get. You just might get lucky if exploring different links at OutOfPrintMusic.com  

MP3 versions of Orchestral Illusions and Baroque Illusions can be bought at any iTunes Music Store. (Just search for Progetto Avanti.) For this, you need the application iTunes by Apple. You can read more about this at Apple's iTunes page

Also, the albums can also be found at Spotify. Here you can listen to streams or buy downloadable MP3s. Go visit spotify.com