Adding Week Numbers with date Functions

hi there,
is there any one can help, i am doing a program for a department that i work in,
basically it is easy to add one number to another in any cell as long as there are no text charachters, having said that you can use a fill button to do so or drag the cell across and so on, but i have created a formula to create "week 14" to display in a cell, but what i want is to start a week number one from the last day of march and first day of april of any year, so it corresponds to week one.

So the cells will look like this

Week 1, Week 2, Week 3 this represent each week of the finacial year.
the formula i have created is complicted and long winded, i want to create a simpliar and easy to understand.

Also i have read many book on excel and been on the net for someone to help out but to no avail, i have attached a file called book 1

regards huston1679