Pivot Table Dates

I have a pivot table that takes data from 6 columns:
A - Current Yr Week (1, 2, 3 ...)
B - Current Detail Date (1/1/09, 1/2/09, 1/3/09 ...)
C - Last Year Week (1, 2, 3 ...)
D - Last Year Detail Date (1/1/08, 1/2/08, 1/3/08 ...)
E - Current Yr Unit Cost
F - Last Year Unit Cost

My goal is to have this daily information compiled into weeks (totaling at
each Saturday). Since columns B and D have daily values, to get true week
end values, I would need to have 3 columns in my pivot tables:
A - Week # - 1, 2, 3 ...
B - 2008 week (listing down the column like this, for each Saturday: 1/5/08,
1/12/09, etc.)
C - 2009 week (1/3/09, 1/10/09, etc)

I'm sure something like this is possible, but I'm not sure how to do it?
Any suggestions would be greatly appreciated!

Thank you for your time and help!

Excel 2007 Pivot Table
Group by week, compare by year.
http://www.mediafire.com/file/zumqx4...10_07_09a.xlsx