Hi - Left handed here too. After lots of messing around I finally got a Logitech G13 programmable keyboard - this fixed everything. Mouse in left hand, G13 for right hand, keyboard in the middle for chat. You can program it for single keys or text commands - couldn't play without it now.

So I would recommend getting one of the programmable gaming keyboards. There seem to be many available.

note 1 - I tried a mouse with more buttons, but since I'm using the mouse to move that doesn't work well. There is too much AOE at higher levels.

Note 2 - you could also get a controller for your PC. I personally don't care for the controller for battle but they work fine on a PC.