Last week's revenue

I feel like this should be simple - BUT - here goes...

I need the formula to find total sales THROUGH last week.  Meaning I need to know how much in sales have we done on a show through last Tuesday.  And, then, next week, I want it to be showing me how much in sales I have done through the previous Tuesday.  I always want to reference back to total sales through the Tuesday prior.  Any thoughts?  Thank you in advance!