How to find sunday in every month in attendance system(using pivot function)

I am using View and store procedure in sql server 2008 R2

My View is::


ALTER view [dbo].[vwAttandenceDetails]
as
select sd.id, sd.name, att.attendance_status,sd.rf_code,
DATEPART(day,att.attendance_date) as 'day_Name'
from tb_student_detail as sd
left join tb_attendance as att
on att.student_id=sd.id


And Stored procedure is
ALTER proc [dbo].[disp_monthly_report]
as
select rf_code as 'Student ID', name as 'Name',
isnull([1],'A') as '1',
isnull([2],'A') as '2',
isnull([3],'A') as '3',
isnull([4],'A') as '4',
isnull([5],'A') as '5',
isnull([6],'A') as '6',
isnull([7],'A') as '7',
isnull([8],'A') as '8',
isnull([9],'A') as '9',
isnull([10],'A') as '10',
isnull([11],'A') as '11',
isnull([12],'A') as '12',
isnull([13],'A') as '13',
isnull([14],'A') as '14',
isnull([15],'A') as '15',
isnull([16],'A') as '16',
isnull([17],'A') as '17',
isnull([18],'A') as '18',
isnull([19],'A') as '19',
isnull([20],'A') as '20',
isnull([21],'A') as '21',
isnull([22],'A') as '22',
isnull([23],'A') as '23',
isnull([24],'A') as '24',
isnull([25],'A') as '25',
isnull([26],'A') as '26',
isnull([27],'A') as '27',
isnull([28],'A') as '28',
isnull([29],'A') as '29',
isnull([30],'A') as '30',
isnull([31],'A') as '31',

(select count(id) from vwAttandenceDetails where id=pio.id and attendance_status='P') as 'P'
from vwAttandenceDetails
pivot
(
max(attendance_status)
for day_name
in ([1],[2],[3],[4],[5],[6],[7],[8],[9],[10],[11],[12],[13],[14],[15],[16],[17],[18],[19],[20],
[21],[22],[23],[24],[25],[26],[27],[28],[29],[30],[31])
)as pio


I want to know which date is sunday(each sunday of month) and print that column as "S".

This is attendance management system