Bring the Box of Ingots to David Wayne at Wayne's Refuge in Terokkar Forest.
<The orc shakes his head at his failure.>
This is beyond my ability, but that's not to say the weapon can't be recreated.
It pains me to suggest this, but your only hope may be a human smith by the name of David Wayne. It's true he was once a member of the Alliance's expedition, but that was a long time ago and he has since left the Sons of Lothar. These days, he lives in a small camp on a peninsula northeast of Firewing Point in Terokkar Forest. Take the ingots to him and see if he can help you.