You may have to derive your date field from existing data:
YourDateField = Year + Month + DataType Int Column converted to varchar
Eg:- '2012' + '01' + RIGHT('00' + CAST(MonthDay AS NVARCHAR(2), 2)
select * from yourTable
Where UPPER(DATENAME(DW,YourDateField)) <>'SUNDAY'
OR
select * from yourTabl
Where DATEPART(DW,YourDateField) <> 1