I do not know what all changes you made to your site. And possibly, you too cannot retrace the steps and undo the changes, including the changes you made to the database through phpMyAdmin. Under these circumstances, I can only suggest that you reinstall WordPress and restore your site from a working backup. You may also contact your hosting support so that they may be able to restore your site without much trouble.
BTW, you are running WordPress 3.5.1. So, if you restore from backup, install that version of WordPress and then restore the site. Afterwords, you must update WP to the latest version.