You can check out the Wiki for a drop list, though I don't know if it is 100% complete it should give you an idea of where to find something.
http://www.fiestafan.com/wiki/index....evels_11_to_20
Personally as a Cleric I wouldn't worry too much about enhancing your weapon at lower levels. Especially if you are counting on chance to succeed and risk of breaking. If you can, find a party and save up for later levels.