Because the email address is an identifier of your account, you won't get this changed without manual service by a developer, I believe ... so you may have to try to make an appointment with one of the few able people. If you know how to use IRC, try to discuss that in the channel #planeshift-gmtalk on Freenode; if not, maybe Eonwind or Venelan can take you further (you could write them a PM if they don't notice this thread soon).