Actually, that Winn-Dixie isn't the best or even the closest. You're better off at Publix. Here are the directions from Pop Century:
Go out the entrance and turn left onto Victory Way. Go to the next light (the entrance to Wide World of Sports will be across the road) and make a left. That's Osceola Parkway. Follow that off property (Mickey will be waving goodbye), and over I4 (there will be a light there). Continue straight. On your right will be the huge Gaylord Palms (you can't miss it). Right after the Gaylord Palms, there will be a light. Make a right onto International Parkway South. Follow that and the Publix will be on your left just before you get to Highway 192. There's also a Walgreens on the right at the intersection with Highway 192.
That's the Publix we always use no matter where we are on Disney property. It's about eight minutes from Pop Century.