Where can I watch The Informer in United States?

Gypo Nolan is a former Irish Republican Army man who drowns his sorrows in the bottle. He's desperate to escape his bleak Dublin life and start over in America with his girlfriend. So when British authorities advertise a reward for information about his best friend, current IRA member Frankie, Gypo cooperates. Now Gypo can buy two tickets on a boat bound for the States, but can he escape the overwhelming guilt he feels for betraying his buddy?