Hi Tanveer,
Charts and Groups in a report do not display values that are not present in the database.
Create a table in your database with all the dates (if that's possible) and Left Join it to the current table in CR.
This way the report should display future months even when there aren't any records.
You would then need a Record Selection Formula as well that will restrict records to the current fiscal year.
Otherwise, follow Jamie's blog here:
-Abhilash