Unfortantely, there is no password recover for the WLC unless you have WCS. If you have WCS can push a new admin username/password to the controller. If you do not have WCS then you have to default the configuration to access the device. You can do so by using the console port and upon booting up you hit the 'ESC' key. It will then prompt you so you can default the configuration.
The WLC config needs to be cleared from the boot menu on the CLI (after hitting the Esc key when you see the Cisco logo) and rebuilt from scratch.