creating arrays from mySQL query

Hello,
 
  I am attempting to create a few different graphs based on some data in  a mysql table, using PHP to create the xml file I will be sending to the flex charting component I am using.

Here is the query, and the result set:

SELECT repID, DATE_FORMAT( dateIntake,  '%M' ) AS DATE, SUM( totalDebt )
FROM clients
GROUP BY DATE, repID
LIMIT 0 , 30

Showing rows 0 - 15 (16 total, Query took 0.0090 sec)
______________________________
  repID      date      SUM(totalDebt)
test rep2      August      225000.00
test rep3      August      750000.00
test rep4      August      25000.00
test rep5      August      512797.50
test rep1      November      187806.50
test rep2      November      425336.50
test rep3      November      19149433.00
test rep4      November      297000.00
test rep2      October      775297.50
test rep3      October      1587500.00
test rep4      October      495000.00
test rep5      October      67500.00
test rep2      September      183378.50
test rep3      September      208460.00
test rep4      September      526600.00
test rep5      September      125000.00
____________________________

Next, what I want to be able to do is to take that result set, and for each rep, come up with their totalDebt values for each of the months in seperate arrays, then another array called months that would contain each of the months, in order.

What would be the best way to loop through the result set and come up with these arrays?

Here is the PHP code with the query (I am using a class to connect to the db)

$db = new DbConnect();
$db->open();
$db->query("repID, DATE_FORMAT( dateIntake,  '%M' ) AS DATE, SUM( totalDebt )
FROM clients
GROUP BY DATE, repID") or die($db->error());
$row = $db->fetcharray();

Any idea where to start on this?