how to design a report that is using a date and tiem to grab the data

I have a report that is using a date range and a time range when it pulls the data.

They want to be able to run for whatever range they want but if they put in below it will not work because the end tiem is less than the start.

Date: 12/6/2007-12/7/2007

Time: 24:00:00 - 18:35:00