First playthrough? I personally don't recommend you running Autumn Aurora first time. AA is hardish. I would recco Zone Reclamation Project for your first time since it's just bugfixes or maybe Complete for a bit more easier time but... here you are.

Sounds like you're in the Garbage at the car lot where Bes is. That part can be tough early on, especially with the crappy starting gear. You uh, probably aren't going to find any better armor any time soon, but you should have been able to pick up a PP-19 Bizon (which uses 9x18 Makarov rounds in AA, 9x19 is a different caliber, familiar in America as just 9mm. Don't get 'em confused, if you still have the starting pistol {Makarov} then it uses 9x18) from a dead bandit by now. Bizon is actually fairly decent in early play. On my current game, I got lucky and the Military guys under the railroad trestle were mostly killed by bandits and I could mop up and so had a AK74 by the time I got to where you are, then I got an awesome random stash drop that led me to the Dark Valley to get a special suit added to the game by AA. But you can't just go get that, you have to get a random stash from a dead NPC... This is my first time playing AA and I've found there to be no good armor options early on. Play smart, try not to get shot. ;D

Uh, so, what else..? With a Bizon I find I can sorta hole up in that parking lot attendant's kiosk there on the east side of that lot, by the road and the gate and fire on the bandits as they come over the ridge from the west. Try not to let them get down amongst the vehicles, though. It only gets harder when they have that to use for cover. Try to use some of those random NPCs as a bit of a buffer between you and the bandits... If you're all the way at the back the bandits will usually engage with the Loner NPCs and you can take pot shots at guys who are aiming at people other than yourself.

Finally, I know it seems counter intuitive but consider putting the diff back up to Master. For my final advice I will quote a fellow stalker on the Steam forums:

"The difficulty works both ways, guns deal more damage both to you and enemies. Aim for the head and upper body. Always aim down sights. Crouch to improve accuracy. Fire in short bursts or single-shot, automatic fire is hard to use from long range. Most importantly, use cover, no cover and you're good as dead."