no login

Assuming you changed the Site address, not WordPress Address, you should still be able to log in at:
http://hannahkuipers.nl/wordpress/wp-admin/ and change it back in the settings.

If you’re still locked out somehow, and you have access to the database via your hosting control panel (phpMyAdmin or similar) you can go in and change it manually there (google change WordPress address phpmyadmin for instructions)