You can pick up the lemons at Location (1,-16) in the city of Astrub from the shop in the middle that looks like a grocery store.
The butcher's shop you can't miss- it's got a huge skeleton atop it. Then you go back and talk to the girl that gave you the quest again. Then, you have to fight! Don't worry- she kicks the tar out of you, then sends you on yet another quest.
Then go down to (4,-13) and you're done!