Please check the links:
**** few work books
Hope it helps.
Is there any provision to transform the structure of the data source?
If yes then find my approach below,
First you need to transpose the date fields into rows like this
Once done then drag the fields like this and show missing values from properties of the date field.
Finally change the DATEPART of the date field to get the week number
Here you go,
Let us know if this help.