It is only at Epcot. I am not sure off the top of my head for DL but it would be online with the location on the Disney Rewards Visa website or in your member benefits information you received after obtaining the card.
In DL, it is in the DCA park and located near the Monsters Inc. ride, tucked in a corner. The hours are generally very limited in DCA and it is not very busy (i.e. few guests go). When I went last summer, the characters you saw at DL alternated between Minnie and Stitch.