webtrends

Pulled webtrends data using Webtrends connector in PowerBI desktop for last 5 years. In Site Pages report, there is a coulmn for Timeperiod, it shows 1/8/2013 - 31/7/2018 and it is a text type column.

How to apply filters to get only last year or last quater data on the datasource, with out connecting to Webtrends again?

Thank you for your help.