Amy was a girlfriend of Jordan Pryce.
History
When Jordan Pryce was about to ascend to the CEO of Wayne-Powers, due to an assassination attempt on Bruce Wayne's life, he had held a private party, with Amy that, was to contain caviar and a good wine. But she ultimately "missed the boat", because the Jokerz had intercepted her and then bound her to a pole at the port and gagged her. Instead, one of the Dee Dee twins had managed to pose as her in the dark room on the bed, waiting to ambush him.
Background information
In the edited version of the film, the scene in question was shortened to the point where it started when Pryce questions where Amy is on the yacht, presumably due to the sensual nature of the original scene.