You can either replace the fob and not keep anything of value in the car if it does get stolen or go the most expensive way and have it re-keyed which include two new remotes with mechanical keys along with them changing the lock on the driver side door.
I'd take my chances with option 1 and simply avoid the location where they were lost for a while.
You may even check with some of the store employees there and see if anyone turned it in by chance worth a shot
