It really wants Ranged Weapon Mastery for the range increment boost. Should probably have a level or two of the Exoticist fighter variant (Google "Chet Kindred Circle" for the old crystal keep files) to get free proficiency in a few exotic weapons including the boomerang, which opens a feat slot.
Edit: Is Ancestral Relic a possibility here? You could use the basket of your fourfathers (mother was a whore).