DECLARE	@SelectedDate	DATE = '2012-02-01' --GETDATE()
DECLARE	@DesiredDay	TINYINT = 5

SELECT	TOP 1 NextDay, DATENAME(WEEKDAY, NextDay) AS NameOfDay
FROM	(
	SELECT	DATEADD(DAY, N, @SelectedDate) AS NextDay
	FROM	Tally
	WHERE	N <= 14
	) x
WHERE	DATEPART(WEEKDAY, NextDay) = @DesiredDay
ORDER BY NextDay

DECLARE @now DATETIME = '20120201'

SELECT TOP 1
	theDay
FROM
(
	SELECT 
		theDay,
		--==
		--==	Rank the thursdays 1-4 (or possibly 5)
		--==
		theRank = RANK() OVER(PARTITION BY MONTH(theDay) ORDER BY theDay)
	FROM	
	(
		--==
		--==	Get all the days in this and next month
		--==	
		SELECT 
			   DATEADD(dd,n-1,DATEADD(mm, DATEDIFF(mm,'19000101',@now ) ,'19000101')) theDay
		  FROM
			   Tally
		 WHERE
			   N <= 
				DATEDIFF(dd,
					DATEADD(mm, DATEDIFF(mm,'19000101',@now) ,'19000101'),
					DATEADD(mm, 2+DATEDIFF(mm,'19000101',@now) ,'19000101'))
	) alldays
	WHERE
		--==
		--==	Get just the Thursdays (note the adjustment for a DATEFIRST setting other than 7)
		--==
		(@@DATEFIRST + DATEPART(dw,theDay)) % 7 = 5	
) Thursdays
WHERE 
        theRank = 1	-- The first thursday
  AND
        theDay > @now	-- After the target date
ORDER BY theDay

DECLARE	@SelectedDate	DATE = '2012-02-02' --GETDATE()
DECLARE	@DesiredDay	TINYINT = 5
SELECT	TOP 1 NextDay, DATENAME(WEEKDAY, NextDay) AS NameOfDay
FROM	(
	SELECT	DATEADD(DAY, N, @SelectedDate) AS NextDay
	FROM	Tally
	WHERE	N <= 40
	) x
WHERE		DATEPART(WEEKDAY, NextDay) = @DesiredDay
	AND	DAY(NextDay) <= 7
ORDER BY NextDay

 WHERE 
        (@@DATEFIRST + DATEPART(WEEKDAY, NextDay)) %7 = @DesiredDay
   AND	
        DAY(NextDay) <= 7