You have a Membership, which means you purchased TIME in the game. You do not need to purchase individual areas in the game with Crowns, as, like I said, you already purchased the time.
Remember, Wizard101 is a story based game. Like a book, you need to complete the first chapter before you can move on to the next, so complete all your required assignments in Wizard City and Krokotopia will be opened for you to investigate.
