SQL Server 2008 getting rows from this date to this date

SQL Server 2008 getting rows from this date to this date

i really couldnt get it.
code- select * from Bill_Detail where DateTimeofBilling>'8/18/2013
12:00:00 PM' and DateTimeofBilling<'8/20/2013 12:00:00 AM'
psudocode- select all from Bill_Detail where DateTimeofBilling greater
than 8/18/2013 and DateTimeofBilling less than 8/20/2013.
i need to get the rows from the date 8/18/2013 to 8/20/2013 but the code
returns nothing.
i think this is enough explanation for this . can anyone help?