How to create Sheet level date filter using a dropdown?

I have to create a date filter (which should be a dropdown), that only filter the components in that particular sheet. I think this can be done using a sheet filter by setting a variable using a button dropdown. The problem is that the date is in DateTime format, and it writes to the variable like this : "Sun Jan 03 2016 05:30:00 GMT+0530 (India Standard Time)", I am new to pql and I don't know how to convert it into a proper format so that it can be used with FILTER statement in load script. Please help me out.