Preparation for pivot table to list dates by specific day of the week

hello guys
I need to create dispatch log input spreadsheet with some pivot data table. And Im stuck with one column....
I have one with date dd/mm/yyyy and I want to create supporting column which always show monday of current week. So if I would type 13/01/2011 or 12/01/2011 I should see 10/01/2011 in supporting column.
That should help me creating pivot table when it will be possible to see each week
Thanks

I think you would need to add a helper column that lists the Monday for the week for each date cell.

So if the dates are in column A starting at A2, then formula would be:

=A2-WEEKDAY(A2,3)

copied down.

Then use that column for your Pivot Table.