Expression to get start of the week from WeekNumber

Hi am trying to come up with an expression to get start & end of particular week by providing week number but get i,proper results.=DateAdd(DateInterval.WeekOfYear, Fields!WeekNumber.Value - 1, CDate("1/1/" & Today.Year.ToString())) This is the exp I am using by passing week 22But I get May 28 .Where as It should be may 25 and ending date should be 31.Can anyone advise pls