Greetings,
The sewers are usually the first stop for rat hunting. There is an entrance by the library, and one by Hydlaa\'s tavern. You can ask someone in-game to show you the locations if you don\'t want to explore yourself. Though of course I\'d recommend the latter ;)
Weapons are bought from merchants, as they should be. Harnquist standing by the blacksmith\'s building in Hydlaa plaza is a very popular guy, but the husband and wife team standing in the park before Hydlaa\'s exit gates offer goods as well, not to mention a few weapon crafters in Ojaveda.