Playing Resident Evil 5 2nd Time Around?

I finished it a few days ago and decided to play it again but with all my weapons and ammo etc. from the end of the 1st time i played, but the problem is, i ran out of ammo and discarded lots of stuff in the fight with Wesker, and now I'm 15 minutes into playing it again, and have virtually no ammo, one shotgun, one handgun, one sniper rifle and a grenade launcher between Chris and Sheva, any tips on how i could get my hands on more guns or ammo? Or how i could conserve ammo? And no i don't have much money to buy new guns.......... Oh and does anyone know when or how you get the guns with infinite ammo?? Thanks!!