So I spend all this money on a new console, and I spend all my time playing ancient games on it? Something wrong there!
Anyway. I finished up all the stars on the first two worlds, got most of them in the third and fourth (taking my total to 30), then did the first star in Dire Dire Docks, opening up the entrance to Bowser again. Went in there, defeated him, and then opened the door up to the next floor of the castle.