Use record selection date in report formula

I tried searching through the Community for this, but I guess I didn't search for the right term.

I'm looking to use the date range from the record selection for a comparison to a field for EnrollDate.

This formula appears to work in the query: 

if ({Tablename.DateEnrolled})>= Date (2013,11 ,1 ) and ({Tablename.DateEnrolled})<= Date (2014,11 ,1 ) then "New" else "Returning"

I'm pretty sure that there will come a time when I run the query having selected a new date range but having forgotten to change the formula.

Is there a way to get the Report Record Selection date into the formula?