If you're using Throw Stone it means you're currently a class that's not intended for combat. Look on http://ffxiv.yg.com/items?f=s=weathered;c=1 for weathered weapons. You should be able to look up the location of an NPC that sells them. They each cost between 1.2 and 1.6k gil. Finally, equip the new weapon to change to a fighting class.