select

*

from

MyTable

where

-- Date greater than or equal to Monday of last week

MyDate >= dateadd(dd,((datediff(dd,'17530101',getdate())/7)*7)-7,'17530101')

and

-- Date before Saturday of last week

Mydate < dateadd(dd,((datediff(dd,'17530101',getdate())/7)*7)-2,'17530101')