Split each month into weeks ie Jan 2014 Week 1/2/3/4

Hi All

What i need to do is, based on a date, to split each of the months of the year 2014 into weeks.
It`s ok if we consider that each month has 4 weeks only.
Or if easier, ok to split the month in the exact number of weeks they had so far.

Example:

Date: 1/01/2014 week 1 ; 6/01/2014 week 2
Looking at March 2014 for example : 1st March was on a SAT and 2nd on SUN. It would be best to consider as week 1 from 1st March to 9th March.

I have attached a worksheet in case anyone is able to help me.

Many thanks in advance,
Ana