Here is an alternate version using a Tally table.

DECLARE@SelectedDateDATE = '2012-02-01' --GETDATE()

DECLARE@DesiredDayTINYINT = 5

SELECTTOP 1 NextDay, DATENAME(WEEKDAY, NextDay) AS NameOfDay

FROM(

SELECTDATEADD(DAY, N, @SelectedDate) AS NextDay

FROMTally

WHEREN <= 14

) x

WHEREDATEPART(WEEKDAY, NextDay) = @DesiredDay

ORDER BY NextDay

It should be easy to turn into a function.