Creating a formula that extracts the week from a date

Hi everyone, I have a very time consuming problem, I'm hoping someone will be able to help me with. Basically I have every single date from today until June 2015 in one column of an excel doc. In the next column, I have the week it resides it. Is there a formula that can be made to easily associate a date with a week? I've been doing this by hand, and it's taking a ton of time!

Thanks!


Date | Week
7/1/2012| 7/1/2012
7/2/2012 | .
. .
.
.
.
7/7/2012 | 7/1/2012