Sorry but that's not possible. There is no way to recover the URL you deleted because there is no recycling of deleted blog URLs here at WordPress.com. This prevents the scenario of someone impersonating the blogger who originally had the deleted URL after they deleted it.
There are 3 warning of this given prior to blog deletion and then a confirmation link in an email is sent, and the blog is not deleted until that link is clicked. That prevents accidental deletions by insuring everyone who deletes a blog has had lots of previous warnings that what they are doing is irreversible.
Confirm by reading http://en.support.wordpress.com/delete-site/ and
You can register another blog with a similar name. http://en.support.wordpress.com/register-a-blog/
Or you can register a domain via a domain mapping upgrade and it will not matter what the underlying .wordpress.com address is.