http://www.diabloii.net/items/runes/...-weapons.shtml i don't see the damage of the runeword (cresent moon). So how do I know how much damage it wil get? and put it in Normal gray axe, superior gray axe or elite gray axe?(for the highest posible damage or just the best).
Sorry for my bad English and I hope someone can help me.
If you decide to make crescent moon make it in an elite axe. And we would need to know your combat skill before it is possible to tell you what axe to make it in.
For your current axe I would say, don't bother putting something in it, but find a better axe. Probably you can find a magic axe from one of the vendors in town with higher damage, use that one. If you are on the realms you can also trade for a unique axe, probably you can get the Butchers Pupil for 5 pgems or so if you look a little, that should help you out for the time being.
edit: and for runewords I use arreat summit and the damage depends on what kind of axe you make it in
If you think you are good now, that is good. If you want more specific advise, you should give more specific information, like skills, lvl, statpoints and other gear of your barb. Also if you feel like you want to learn more, check the stickies in the barb forum.