Pages with duplicate title tags

[mexabet]

I have this script and it works fine but Google is complaining that the dynamically-generated URLs have duplicate title tags and duplicate meta descriptions- having inherited that from /cmp/index.php.
A few examples of the pages are as follows:

/cmp/index.php
/cmp/index.php?start_time=12.00+am&start_tz=Africa/Abidjan&end_tz=Africa/Abidjan
‎/cmp/index.php?start_time=12.00+am&start_tz=Africa/Abidjan&end_tz=Africa/Accra
/cmp/index.php?start_time=12.00+am&start_tz=Africa/Abidjan&end_tz=Africa/Algiers

The following is the section of the code causing the duplicating issue:

// Check to see if the form has been submitted
if ($_GET["start_time"] != NULL){
    $start_time_input = htmlentities($_GET["start_time"]);
	$start_tz = $_GET["start_tz"];
	$end_tz = $_GET["end_tz"];
	putenv("TZ=$start_tz");
	$start_time = strtotime($start_time_input);
	echo "<p><strong>";
	echo date("h:i:sA",$start_time)."\n";
	echo "</strong>";
	putenv("TZ=$end_tz");
	
	echo "in $start_tz becomes ";
	echo "<strong> ";
	echo date("h:i:sA",$start_time)."\n";
	echo "</strong>";
	echo " in $end_tz.</p><hr />";

This is how the script prints out the query result:
12:00:00AM in America/Los_Angeles becomes 03:00:00AM in America/New_York.

My question now is how do I use this dynamically-generated results as the titles of the generated URLs? And how do I assign META Keywords and META Descriptions to each URL?
Finally how do I assign SEO friendly URLs through MOD rewrite?