You're connected to the router, but either with what's called a local connection (because of the way the router is set up) or the router itself isn't connected to the internet. Without being there, even the best guess would be just a wild guess.
"Forget" that connection and try again. See if anyone else is using that wifi at that location and getting internet. Ask someone at the shop (if it's something like Starbucks or Walmart) or your internet provider (if it's their town-wide wifi).
As I said, there are just too many possibilities for us to be of much real help to you. Even asking at a local computer store or your carrier's store might get you an answer.