I want to filter a recordset by a deabasket variable

I'm on the pp_confirm.php page and want to send an email to a list of people in a loop from a recordset.

My problem is I need the ID to filter the recordset by and the only place I can see that ID is returned by PayPal and shows up in the DEA Basket Variables as $DEAbasket->DisplayInfo("ID")

I've tried to add this to the recordset and tried SESSION GET POST COOKIE etc but none of them work. If I print the code on the page (echo $DEAbasket->DisplayInfo("ID");) it shows up correctly so I know that it is there to use so to speak but how do I filter the record set?

This is my URL parameter code (which doesn't work)

$colname_rsCourse = "-1";
if (isset($_GET['$DEAbasket->DisplayInfo("ID")'])) {
$colname_rsCourse = $_GET['$DEAbasket->DisplayInfo("ID")'];
}
mysql_select_db($database_connDeaLearning, $connDeaLearning);
$query_rsCourse = sprintf("SELECT CourseID, courseTeacher1, courseTeacher2, courseTeacher3 FROM course WHERE CourseID = %s", GetSQLValueString($colname_rsCourse, "int"));
$rsCourse = mysql_query($query_rsCourse, $connDeaLearning) or die(mysql_error());
$row_rsCourse = mysql_fetch_assoc($rsCourse);
$totalRows_rsCourse = mysql_num_rows($rsCourse);

Am I on the right track?

John