Sorry, Date is your date value.
For example if the date was hardcoded it would look like this.:
select DATEadd("d",7+4-datepart("dw",'07-31-2010'),'07-31-2010') , DATEadd("d",7-3-datepart("dw",'07-31-2010'),'07-31-2010')
If I wanted it to always be today I would change date to GetDate()
select DATEadd("d",7+4-datepart("dw",GetDate()),GetDate()) , DATEadd("d",7-3-datepart("dw",GetDate()),GetDate())