90 Days, But Not Current Month

I have a query setup:
SELECT Format([RepDate],"mmmm yyyy") AS [Date Reported],
inc_Incident.Category, Count(inc_Incident.Category)
AS CountOfCategory
FROM inc_Incident
GROUP BY Format([RepDate],"mmmm yyyy"), inc_Incident.Category,
inc_Incident.Status
HAVING (((inc_Incident.Status)<>"Cancelled"));


I'm trying to figure out the best way to get the query to return category counts per month (formatted MMMM YYYY) for only the last 3 full months (not including the current month).
If it matters Repdate is formated Long Date.

Any help people can offer?