I don't own the game, but doesn't it base on the Quake Engine? If so, you could define the fullscreen mode and the resolution in the config (.cfg-file) located somewhere in the Wolfenstein directory or in the Application Support dir of the game
~/Library/Application Support/RTCW
or something like that...
search for a .cfg
in there u have to have these ptions (they probably have different values ATM, so change em):
r_mode -1
r_customaspect 1
r_customheight 1200
r_customwidth 1920