Please discount the Steam version of the game/expansion on Steam too.

[Bixillarla]

If you're still new to the game, I say switch over to a non steam version before you become too invested in your current character.

That doesn't matter, I started on PS3 and bought the PC version and still had my characters. Once you log in it does not matter which version you have you have access to all yoru characters. You can get the non steam version and still use your characters once logged in.