As you've only made a few posts, your best bet is to ask for your account to be de-activated and create a new one.
We usually don't do name changes unless a valid good reason is given. You can imagine the work it is going to cause the Admin team everytime somebody fancies a name change.
Admin can be contacted by sending them a PM. Click on their profile and you'll find a PM button to compose the message.
I'll also merge this with your existing topic.
Mark