Generating Records Weekly / Bi Weekly Based On The Received Date Field

I have a query that will generate records monthly based on the number of months that i calculate between two date feilds for a given requestid. How can i use the same query to generate records for weekly and bi weekly based on the receiveddate field that i use in the subtraction for calculating the number of months.

Also when inserting i have been adding a month for every record as i was generating monthly and now i would have to add week and 2 weeks to the receiveddate

SET NOCOUNT ON
GO
declare @num_of_times int
declare @count int
declare @frequency varchar(10)
declare @num_of_times1 int

[Code] ....