Fall of constantinople...need help fast since its due next week

I have been using blender for a few years and when I was assigned to do a “creative” project for my college world history class, the obvious “easy” way out was to do something in blender. I decided to make a model of the fall of Constantinople. Since I suck at character animation, I am making the scene at night as sort of a “after the battle” picture with fires, dead bodies, holes in the walls, etc.

Since this is a work in progress, the river is not completed (it moves, but I have not yet put the mini-waves in place so it looks rather video-game-ish along with the props (people, cannons, etc).

My main problem right now is lighting and fog. I am really not very good at this. Currently I am using a sun lamp at half intensity with a bluish color on it (representing the moon…or at least that is what my thought is). The main problem is that because this light lights up everything, I had to add fog to compensate for the fact that the scene is not infinite and I would like it to look sort of like it is. Eventually there will be torches and stuff mounted on the outside of the walls and fires burning behind the wall (and in the spaces in between), but I would like the viewer to be able to see the walls. What would you guys recommend I do?

http://cuznersoft.com/constantinople/0399.jpg
Obvious fog problem

http://cuznersoft.com/constantinople/0286.jpg
Showing the walls

Animation (439Kb AVI)

Fake most of it with particles and the rest with well placed lamps, after scrapping the sun lamp, they won’t be able to tell the difference.
Oh yeah, rig the textures too, and things will look much further away if you do an up close zoom. Go right up to the walls and into the buildings and out again. Keep the view low enough that you can obscure the rest of the plains with mountains.