Hi,
Create this condition at universe level and try
('CURRENTWEEK'=@Prompt('Select Frequency','C',{'CURRENTWEEK','CURRENTMONTH','YTD'},MONO,FREE) AND To_char(Req_Date , 'WW-YYYY')=To_char(Sysdate , 'WW-YYYY') )
OR
('CURRENTMONTH'=@Prompt('Select Frequency','C',{'CURRENTWEEK','CURRENTMONTH','YTD'},MONO,FREE) AND To_char(Req_Date , 'MM-YYYY')=To_char(Sysdate , 'MM-YYYY'))
OR
('YTD'=@Prompt('Select Frequency','C',{'CURRENTWEEK','CURRENTMONTH','YTD'},MONO,FREE) AND To_char(Req_Date , 'YYYY')=To_char(Sysdate , 'YYYY') )