Filtering based on date in Pivot Table

[jswalemail]

Hello, The attached pivot table displays my data as I want it, however I would like to filter the data by date also and cant figure out how (without creating more data columns). I can apply two filters successfully to reduce superfluous data ('AL or WA' and 'Unique'). I also need to select any desired time frame, e.g. last month, this year, or a user defined range. I can apply an inbuilt date filter by clicking on 'EventStamp' in the field list (under 'Choose Fields to add to this report'), however this doesn't have any effect on the table or chart.
Where am I going wrong? Also having difficulty putting the problem into words so have been unsuccessful searching posts. Working with Excel2010. Thank you.