Is there any other way to get a XBOX Batman Arkham City Catwoman Code besides buying it? I had an issue with mine. (Story inside)

Up in Canada we have Boxing day after Christmas and I don't usually have much money but love batman and thought the sale price was my only shot at getting the game for a while.

Ebgame (Gamestop) had Arkham on sale and I was told that they were all sold out when I went. Just as I was walking out, the associate says he has the disc but cant seem to find the case for it (ebgames keeps the discs in a security type drawer) Wanting the game and being somewhat indifferent to cases, I say "Just give me the display case" and everything is good.

When I get home, I see the Catwoman prompt upon playing and go to look inside the case when I realize the problem I now have.