I have played with 1 GB of RAM (on a faster PC, PIV 2.8) and it took a while, but not as much. Maybe 3 or 4 minutes.
Have you tried to uncheck the load textures at initialization option??
It should make the loading shorter, but i suppose it will take longer to start the scenario. Check if it's better for you
Maybe you Hard disc is too fragmented, or something like this
A trick i use (not to speed up loading time, but to make it less boring) is to alt tab while the game loads and do anything else (like reading this forum

)
At least on my PC, AACW alt-tabs flawlessly while loading and playing
