Sorry for not following up on this one. Joomla and Mambo have a function called mosemail that can be used to send emails

mosMail($fromemail, $fromname, $toemail, $subject, $body);
I haven't tested this, but after someone does and we get it working I will post it on the tips and tricks.
In jreviews.common.php, function saveReview, you can put this line either at the end of the following if stament either inside or outside the closing curly brace "}" depending on whether you want the notification setting to also affect this email to listing owners.
Loof for this if statement and find the closing brace for it further down
// messaging for new reviews
<?php
if ( $jrsettings->notify_review ) {
?>
Place this code either before or after the closing brace. Before turns off the email together with the email notification.
<?php
/****************/
//get listing owner email
$sql = "SELECT user.email"
."\n FROM #__content AS content"
."\n LEFT JOIN #__users AS user ON content.created_by = user.id"
."\n WHERE content.id = ".$formValues['pid']
;
$database->setQuery($sql);
$toemail = $database->loadResult();
if ($toemail)
{
global $mainframe;
$subject = "New review for ".$title;
$body = $message;
@mosMail($mainframe->getCfg('mailfrom'), $mainframe->getCfg('sitename'), $toemail, $subject, $body);
}
/****************/
?>
Ignore the php tags <?php and ?> in the code above.