The Witch Queen stole my hammer !

After taking the "Kill the Witch Queen" quest from Waheetu and receiving the "Hammer of the witches" I poisoned the Goblin Chief . The witch queen appeared before me , took my hammer of the witches , and threw me into the area "Empire of the Witch queen". Where can I find this hammer or another one , as it's the only way of defeating the Witch Queen.

Edit: According to the quest wiki , there's no way of retrieving the hammer of the witches , so be careful , don't do those quests in the order I did.

Update: I got one from the Celtic Rift expansions, but I don't exactly remember who gave it to me.