You can get them at Epcot, or you can purchase them over the phone before you get there. If you buy them early you'll be sent an exchange certificate, and you can use the number on the back of that to plug into MDX and make FP+ reservations at the 30 day mark.
Just be prepared to show your Florida ID at the ticket counter when you activate your exchange certificate. They won't activate a FL resident ticket without proper documentation, even if you already purchased the ticket.