You would adjust the date field in the group by area... try:
SELECT LEFT(Format(Stats_Date,'mmmm'), 3)+' '+STR(DATEPART('yyyy', Stats_Date)) AS XLABEL, SUM(Minutes) AS YVALUE FROM Stats GROUP BY LEFT(Format(Date_Add(Stats_Date, interval -5 day),'mmmm'), 3)+' '+STR(DATEPART('yyyy', Date_Add(Stats_Date, interval -5 day))), DATEPART('yyyy', Date_Add(Stats_Date, interval -5 day)), DATEPART('m', Date_Add(Stats_Date, interval -5 day)) ORDER BY DATEPART('yyyy', Stats_Date) ASC, DATEPART('m', Stats_Date) ASC