It seems even though the time setting is correct when we pull the data the time setting is changed to GMT. So for the purpose I added the following code:
date_default_timezone_set("GMT");
$timestamp = strtotime("2013-10-08 08:45:00");
date_default_timezone_set("Asia/Kathmandu");
$utc_datetime = date("Y-m-d H:i:s", $timestamp);
echo $utc_datetime;