How to SUMIF multiple ranges?

Hello!

As You see I have got a production statistic dayly. I need to sum it weekly
on the end of the month. I need to do this manualy every time. I would
like to define a name: range for each week. SUMIF and DSUM is not ok,
because these just summing the firs column of the range. Ineed to do this with one formula. To sum it first in one column and than use this column in SUMIF is not ok.

Thanx for help.

Charles Cseh