The processing for donations is all automatically handled by the forum upgrade script so there's no need to email a moderator once you have donated :)
What you need to do is:
- Make your donation as normal from the donation page.
- Once returned to the forum main page, in the red bar at the top - click User CP.
- You'll then load up the user control panel and see a menu block on the left titled "Settings and Options" - click Edit Options.
- This will bring up a new page which has a number of editable options, the most important one being Customer User Title.
- Fill in what you want here and then hit the Save Changes button down at the bottom of the page.