I can't think of a way to do what you want using formulas.
You could have a visual basic macro that runs automatically every time the workbook is opened, and if it is a Tuesday, it will copy the required cell or cells, like this:
Private Sub Workbook_Open()
'test if today is a Tuesday
If Weekday(Now) = vbTuesday Then
'copy cell(s) as required
Is this likely to be of any use?