Extending Rows in Pivot Tables

Morning All!

Im currently updating a file that is now out of date.
The pivot tables stopped updating at the end of 2008, is there anyway of adding extra months into the pivot table so it will update to the current date?
Ive attached to screen grabs, the first screen grab is what the table looks like the 2nd is what i would like.

Apologies I useless with pivot tables.

Thanks