Well...
If you extract the files from the .zip, one of the .cs files will define the weapon.
Somewhere in it, there will be a line similar to
directDamage = 30;
Change the number to increase the damage. I reccomend something around 1000. If people complain about it killing too quickly, just ignore them, because the alternative is to reduce the number to some sane ammount like 50 where it takes a full *two* hits to kill.
Seriously, though, it's as easy as finding the right line to change. Look for the datablock for [something]Projectile, and it defines plenty of numbers to tweak and adjust.
Just don't think that people will do it for you, especially if you aren't happy with the first change.
(Also, make sure that if a line ended in a semicolon (;), that once you edit it, it still ends in a semicolon. If you don't, Bad things will happen (like the add-on not loading correctly, if at all))