Russian made
380 auto. Many good brands of ammo out there.
Try want ads, gun shows, gun shops.
2mm in case length.
100-1000 depending on exactly what you want/have.
You don't define what "better" means to you. Price? Size?
Near the firing pin
25-75 USD
Best left to a gunsmith
$75-$125, depending on model and condition.
The .380 automatic cannot shoot 9mm Parabellum ammo.
Please provide a serial number and ask again
Best to ask a gunsmith for help.