Don't know how to get values from stored procedure - php

Question

I wrote a stored procedure this morning and I don't know how to get the values out of it through a class function in php or phpmyadmin. The other examples from the site was not helpful to me.
Here is what I wrote to get results:
public function totalProcedures($friend_name,$session_id)
{
/*
*query to fetch stored procedure
*/
try
{
//executing the stored procedure
$sql_sp="CALL timeline (:friend, :session,#updates, #group_posts)";
$stmt_sp= $this->_db->prepare($sql_sp);
$stmt_sp->bindValue(":friend",$friend_name);
$stmt_sp->bindValue(":session",$session_id);
$stmt_sp->execute();
$rows=$stmt_sp->fetch(PDO::FETCH_ASSOC);
$stmt_sp->closeCursor(); // closing the stored procedure
//trying to get values from OUT parameters.
$stmt_sp_2=$this->_db->prepare("select #updates,#group_posts");
$stmt_sp_2->execute();
return $stmt_sp_2->fetch(PDO::FETCH_ASSOC);
}
catch (PDOException $ei)
{
echo $ei->getMessage();
}
}
Can someone help me how to get results?
Here is the stored procedure:
DELIMITER $$
CREATE DEFINER=`root`#`localhost` PROCEDURE `timeline`(IN `friend` VARCHAR(255), IN `session_id` VARCHAR(255), OUT `updates` VARCHAR(62555), OUT `group_posts` VARCHAR(62555))
BEGIN
SELECT *
FROM updates
WHERE author IN (friend, session_id)
ORDER BY time DESC
LIMIT 5;
SELECT *
FROM group_posts
WHERE author_gp IN (friend, session_id)
ORDER BY pdate DESC
LIMIT 5;
END$$
DELIMITER ;