You can register your game with steam if you have no problem using steam, if you do that you have to use the gamespy cd key to register game with steam and that would make the steam redownload the game and patch u to the latest version. In a sense steam will update the game for you no matter what you dont have to do anything yourself manually. This is easiest way.
If you dont like steam or cant use it then you can download retail patches from 1c here:
http://www.1cfiles.com/MoWAS_patch/
Since your version is non goty but a regular version you want to get
http://www.1cfiles.com/MoWAS_patch/m...05.13-full.zip first and patch your game to that, then you will have to get
http://www.1cfiles.com/MoWAS_patch/m...-small.exe.zip patch it and then finally get
http://www.1cfiles.com/MoWAS_patch/m...-small.exe.zip and patch that. At this point it should be all good.