<?php
sab_ip = get_the_author_meta( 'sab_ip', 25 );
sab_port = get_the_author_meta( 'sab_port', 25 );
url = url_of_the_nzb;
?>

http://<?php echo $sab_ip?>:<?php echo $sab_port?>/sabnzbd/api?mode=addurl&name=<?php echo $url?>