How to get the $form_state in hook form submit?
If you only need nid of node comment is being inserted inside and uid of comment author then use these codes :

nid exist in : $form_state ['values']['nid']

you can even load node if you need more info about it using : 

$node = node_load($form_state ['values']['nid']);


to get info about author use : $form_state ['values']['uid']

if user is anonymous this returns 0