The created date is stored as a unix timestamp, which is an integer. Use php's date() function to get the parts of the date from it:
$created = $question['raw']['created'];
$day = date('j',$created);
$month = date('n',$created);
You can also use:
to get the age of the post. This will return a string like
for a post six days old.
Edited to use $question as per the original question's requirements - for access higher up in the hierarchy, use either $this->content['q_view']['raw']['created'] or $this->content['q_list']['qs'][$index]['raw']['created'] as required.