Weapon damage?

[Renad]

How does weapon damage work exactly. I've been playing a human monk, got up to level 7 so far. I had been using 2x rusty maces that hAae like 5 damage each. I was hitting mobs for around 10-15ish damage on a good swing. This morning, after selling all my sulk and bone chips, I was able to use every bit of cash I had and bought a 2hnd Wu's staff for 90pp , can't remember the full names, but u know I've seen other people saying it's a good weapon. Anyway, after equipping it and heading out, I seem to only be hitting for 15-20 damage. This staff has like 28 damage I think, so was expecting it to hit a bit harder. Does it have to do with the fact that my 2hnd blunt skill is low or is it scaled down do to my level? Thanks for any info