Current Report Month & Year calculation?

I have a cross tab which has Report Month = [1,2,3,4,5,6,7,8,9,10,11,12]

I also have Report Year = [2011, 2012, 2013, 2014, 2015, 2016]

Cross Tab -

| Jan | Feb | March | April Month to Date |

Facility |

I want to column header to read the month and display the month name. e.g 1 = Jan

Requirement is if the user runs the report for current year and month I want the column heading to read current month which in today's case is 'April MTD'

SO somehow we need to compare today's date with fields [Report Year] & [Report Month]