Apply Week # based on starting every Sunday

Hello,

I need to take some logic and apply it to a date. I am trying to take a date, and apply that date to a Week #. Each week # starts over every Sunday. So let’s say:

- 06/02/2013 – 06/08/2013 = Week 1
- 06/09/2013 – 06/15/2013 = Week 2
- 06/16/2013 – 06/22/2013 = Week 3
- 06/23/2013 – 06/29/2013 = Week 4

To Clarify:
- Each week # goes from Sunday – Saturday

Another Example:
- 06/30/2013 (which is a Sunday) should be applied to Week 1 in July
- In this instance, Week 1 = 06/30/2013 – 07/06/2013

Please let me know if I need to clarify anything.