[eluser]Arministrator[/eluser]
A model in a helper? You can load a model, or a helper. Or a library, and so on.
Either load a model from your controller with $this->load->model('some_model'); - put it in the construct if you want multiple methods to be able to use it, or put it directly in a controller method.
Or you can autoload it. Add it to the load model array in your autoload file like so:
$autoload['model'] = array('some_model');
