I don't know which typo you are talking about but if you want another username and if it's not in use you can register again with that name.
The OP might've wanted Steven_M.
Yep, that should be what OP wanted:
- snip -
Cheers,
Steven :-)
To S(t)even_M:
I don't want to repeat here what other members have already suggested, but creating a new account is really the fastest way for you.
You have nothing to lose from your current account with just 2 posts.