You could just programmatically add a new user to the site.

This is a snippet from a utility I use to gain access to WordPress sites when I don't have the login info. Just upload it to your wordpress root and navigate to it:

    $user_id = wp_create_user( 'newusername', 'newpassword' );
	if ( is_int($user_id) )
	{
		$wp_user_object = new WP_User($user_id);
		$wp_user_object->set_role('administrator');
		echo 'Successfully created new admin user. Now delete this file!';
	}
	else {
		echo 'Error with wp_insert_user. No users were created.';
	}

Make sure you delete the file when you're done.