How to add a Today+(x) filter on a report/dashboard

Hi all,

We currently have a couple of dashboards based on the 'Resolve By' field and have these set as 'Today' and 'Tomorrow', I need to have another dashboard graph which includes the day after tomorrow but can't find that as an option. 

Any ideas how I can recreate this without using 'On' - as this would be have be changed manually each day.