You don't need to share the original data without any data it'll be difficult for us to give any solution on the fly. You can mock up some dummy data which is similar to your original data structure. A quick question; Week is a Date field or simple string?
If its a date field then you can try something like that
1.Just drag the Week to columns shelf then change it to week number see the scree shot
2. Now Drag your Group ID to rows shelf
3. Cost 1 measures to label
4. Drag Cost 2 measure to the rows shelf and change the aggregation to AVG() and make it discrete.
Let me know If this help else share the small set of dummy data.