Magento: Sort product by 'created date' and 'new from date'

$todayDate  = Mage::app()->getLocale()->date()->toString(Varien_Date::DATETIME_INTERNAL_FORMAT);
 
$collection = Mage::getModel('catalog/product')
                    ->getCollection()
                    ->addAttributeToFilter('news_from_date', array('date' => true, 'to' => $todayDate))
                    ->addAttributeToFilter('news_to_date', array('or'=> array(
                        0 => array('date' => true, 'from' => $todayDate),
                        1 => array('is' => new Zend_Db_Expr('null')))
                    ), 'left')
                    ->addAttributeToSort('news_from_date', 'desc')
                    ->addAttributeToSort('created_at', 'desc');