Having trouble getting my hands around this problem.

I receive sales numbers from stores every week, I have built a workbook that
totals all the weekly numbers from each file on one sheet.

I would like to have a worksheet for Month, Qtr, YTD, I would like these
numbers to accumulate from the weekly #'s I bring in each week. My problem is
I don't want to keep the weekly numbers every week, I'd like to zero them
each week and bring in the new (adding to the totals on the other worksheets)

Is this possible, well I'm sure it is, but how is it possible.

Thanks for your help.