Not to be an ass, but I think you're doing something wrong. The game isn't really that difficult...at all. I've beaten 2033 three times and never used the currency bullets, just used them for purchases. The enemies don't have too much health and humans die from a single headshot. The only "difficult" part is making sure you purchase enough filters for the last half of the game, if you like to take your time and explore like I do.
I'm fully aware of how to play it, but maybe I'm just not far into it yet. I also don't find the game hard as much as I have tedious. It just seems like since I went the action route there would be more ammo lying around and I might as well have just gone the original survival route.