The nearest store is probably Goodings at the Crossroads Shopping Center. I'm not sure what the name of the street it's on but it's across from the entrance next to Downtown Disney.
I also found this tool where you can put in your starting point and destination and it will give you directions: http://www.wdwinfo.com/wdwinfo/transportation/transportation1.cfm
Just put in Crossroads Shopping Center as your destination under "shopping" in the drop down menu.
hth!
Cheryl
p.s. we usually shop at Publix because IMO, Goodings is usually way overpriced - probably due to it's close proximity to the parks and hotels. But if you're just buying a few snacks it probably doesn't matter too much.
There is a Winn-Dixie not far from The Crossroads that is much more reasonable than Goodings. When you approach the Crossroads, turn left onto CR536 (Apopka-Vineland). The store in on the right a couple of blocks from The Crossroads.