username change? administrators, please help!

I signed up for an account by connecting it to my facebook, and I didn't realize that my full name would be stuck as my username. I really don't want people to be able to search for me so easily. How do I officially request a username change? I checked in the FAQ and it said that an administrator can change someone's username in special circumstances such as this.

To change your username you have to:

1) have good reasons to do so (we don't allow free username changing)
2) PM any administrator or moderator