Load Current Month Data into Target table

Hi All,

            I have a requirement where in I receive flat file with  fields item,cost,date.I am taking a stage table where the 3 fields will be included.But to target table I should map only 2 fields - item,cost of the current month only.Flat file will include all the months data.I am assuming I should use Global variable to achieve this task.Please help me out.

Thanks