Also, the Valera (sp?) stones do it. But they are 1000K value each, and rare to find. only in a couple runes in the country side. They charge ALL your magical items in inventory, but then its gone.
They're also used to initially enchant items as well in the Arcane University.
Personally, I leave my weapons unenchanted because they get used up and recharging is super expensive or takes up soul gems. I just enchant the crap out of all my armor
The amount of damage you can do is dependant upon the weapon's condition, your character's skill with that type of weapon, and your character's stats (str for blade and blunt, but I don't know what governs marksman). Your level might also be a factor, but I haven't checked on that yet.