Need help in COD4 campaign.

Ok so im on the level where you are on a sniping mission with one other person (the ghuille suit one, hardened difficulty level.)

Im stuck at the part where I am waiting for the helicopter to come and evacuate me. When the Air Assault helicopters come in and unload their payload of enemy soldiers, and then another bunch of soldiers rush out from behind one of the buildings.

Any tips? Theres not much cover, and the kiosks just get naded repeatedly until you die. Need help beating this. Thanks for your help.

heres a trick i figured out, i was low on ammo, so run to where the bad guys came out at and switch your pistol witha weapon. reload it, and go back to your sniper. you should have a lot more ammo. at least that worked for me. then i just camped at the end where the bad guys came out at. the only problem is, is that you have to pick up your buddy and take him to the copter. which is extremely hard(veteran mode).