Problem with query results on oracle

Hi, I just want to ask, every time I query this sql statement on toad i dont get the right results

SELECT field1, field2, 
CASE WHEN field3 IS NOT NULL THEN
CASE WHEN LENGTH(TRIM(TRANSLATE(SUBSTR(field3, INSTR(field3, ',') + 1), '0123456789', ' '))) IS NULL
THEN SUBSTR(field3, INSTR(field3, ',') + 1) ELSE 'NULL' END 
ELSE 'NULL' END,
NVL(TO_CHAR(STAMPTODATE(field4),'HH12:MI pm, DD Mon YYYY'),' ') AS time1,
NVL(TO_CHAR(STAMPTODATE(field5),'HH12:MI pm, DD Mon YYYY'),' ') AS time2
FROM TABLE1
WHERE TO_DATE(NVL(TO_CHAR(STAMPTODATE(field4),'MM/DD/YYYY'),' '), 'MM/DD/YYYY') 
BETWEEN TO_DATE('04/16/2009', 'MM/DD/YYYY') AND TO_DATE('01/05/2010', 'MM/DD/YYYY')
ORDER BY field4 desc

Select allOpen in new window

I always get this result:
12:45 pm, 13 May 2009
11:59 am, 14 May 2009
11:58 am, 14 May 2009
10:45 am, 13 May 2009

and so on... it's sorting the value by time and not by it's date
i want to get something like 14 May followed by 13 May... and so on...

if i remove the NVL part from the select statement and select only field4 or 5, it sorts by date, but of course, it's in unix timestamp so i wouldn't get a human-readable date... I would only get something like
1281682145... and so on... is there a proper way of doing this? or converting the date without affecting the order by clause?

My database is ORACLE by the way