Index / Match / sum formula to show weekly figures

Hi all,
attached is a returns sheets that a qty is logged against part number every week.
Some of the data I can use pivots on ( no problem ), but I have an issue on the returns tab where I think index/match / sum or something else will be better.
At the moment because of the layout of data I have to drag each week number into the pivot value, do a greater than zero filter then summarize as a sum (yuk) I just cant get my head around index/match /sum, but can someone help?
It would be great just to be able to enter a week number, and all the warehouse, part numbers and qty came through.
There is a short explanation on the returns tab of what im looking for. Thanks in advance.
Oh its a macro book because I was trying to do the dragging week number thing in a macro but cant do it, so reason for upload.