In the game, this card is the "King of Hearts". In Hard Landing, it can be found on the lower level of the building, in a room you come through on your path outside.
Mission: Hard Landing (King of Hearts)
Effect: Fire explosive pistol rounds while downed
Location: About halfway through the mission you will see a big building with a mini-trench outside. Enter the building, and go into the lower level. The card is to the right when you go into the room with the stairs.