you can't !hope I helped!
In Call of Duty: Black Ops Zombies, upgrading ammo at the Pack-a-Punch machine costs 5,000 points. This allows players to enhance their weapons with increased damage and additional features. Players can also upgrade their weapons multiple times, but the cost remains the same for each upgrade.
Everything!
to upgrade your self
The Afterburner
yes yes you can
If you mean on zombies, through using the pack-a-punch machine for 5000 points. If you mean online, sadly it isn't possible.
No.
You need to unlock the weapons.
The perks are the same, but the weapons change. The only weapons in Black Ops that are also world at war weapons are the M1911, MP40, and the Ray Gun.
no, but you can get camo on your weapons
you upgrade the ammo by pack a punching your weapon it should costs $5000 to pack a punch which will upgrade your weapon and ammunition
The Call of Duty Wikia has a complete list of the Call of Duty Black Ops weapons from the related link