My idea on weps for this, is that if you run out of ammo then you have a pistol or some small fire arm for back up, and then once you run out of ammo for that, during the instance you can pick up a dead player/npc's weapon and use it. But, once out of the instanced combat you have to get your original weapon back, but with no ammo still. Just an idea.
*EDIT* Oh, and as for currency, I'm going to think that the different races may have different currency, or maybe the different major race cities do or something.