When you get up to the sniping area, crouch down in the window. There will be some ammunition and health in the corner if needed. Get it if desired, then snipe the first wave of soldiers with normal guns. When your "comrades" say that there are Panzershrecks, concentrate all of your fire there. Do not worry about the regular soldiers because they cannot aim well. Shoot the Panzershrecks until you see a man running up the road with a heavy machine gun. Shoot him then go to the left window and continue.