WordPress Locked out

Hi All

I wonder if someone can help. I have done something extremely silly, call it a moment of friday afternoon madness if you will.

I was attempting to modify the site address so that i can work on developing the site before launch. However rather than adding the additional text at the end of the url so that it can be a subdomain mistakenly added it to the front.

So now i have one site link pointing to mesper.co.uk and another to 321mesper.co.uk

Please can someone help me, I am quite embarrassed so apologises in advance.

Thanks

Steve