Most likely I'll just talk to my cartographer and have him invert it.
Edit: I lied. I have gone through and fixed all the directions so the map is correct. It was actually less work than asking my cartographer to waste four hours trying to invert the map and make changes to the Aor River so it winds the correct way. So, really it doesn't change anything to the story. It just means some minor scenes have been changed. I'll be reposting all the changes. Don't worry, unless you're so into every minor detail of WISB it shouldn't even affect the story for you.