A Better Way To Handle Repeating Dates

I am a developer who works with MS SQL Server a lot, but I'm far from
an expert. I am revamping an appointment scheduling system that
allows for appointments to reoccur daily, weekly, monthly and yearly.

Currently, I am saving the appointment date as the initial appointment
date. Then when I want to check for appointments, my stored proc does
does a select on the appropriate records fitting certain critieria
(like only appointments for this doctor, at this location, etc). Once
I have these records I cycle through them calling the DateAdd() and
DateDiff() functions to see if the appointment is reoccuring during
the dates I'm looking for.

Here's is a mock up of what I'm doing. I know cursors are a huge hit
performance-wise (especially how they are used in this scenario) and
want to get a way from this, but I can't figure out how to get
reoccuring appointments to work. Any help is appreciated. Thanks.

sp_GetAppointments(@StartDate, @EndDate)

set @DateToCheck = @StartApptDate
while @DateToCheck <= @EndApptDate
begin
--Start a cursor
DECLARE RepeatCursor CURSOR
FORWARD_ONLY STATIC FOR

select ApptDate from ApptTable where DoctorID = 1 and

--Check if it repeats daily
((repeat = 1 and
DateAdd(d,DateDiff(d,ApptDate,@DateToCheck),ApptDa te) =
@DateToCheck
and DateDiff(d,ApptDate,@DateToCheck) >0)

--Check if it repeats weekly
or (repeat = 2 and
DateAdd(wk,DateDiff(wk,ApptDate,@DateToCheck),Appt Date) =
@DateToCheck
and DateDiff(d,ApptDate,@DateToCheck) >0)

CLOSE RepeatCursor
DEALLOCATE RepeatCursor

set @DateToCheck = DateAdd(d,1,@DateToCheck)
end