A) No, don't have any MRTG scripts.
😎 to convert unix time (I'm assuming here you mean a unix timestamp) simply use the date function:
http://www.php.net/manual/function.date.php
If you have the timestamp in $timestamp, do the following:
$datestring = date("m/d/Y H:i:s", $timestamp) and it will convert it to month/day/4year 24hour:minute:second format. Look at the above page for further information on this function.
Hope that helps!
Chris King