DateTime Looping Issue

Hi,

DateTime = TransactionDate

DateTime = Now

DateTime = 01/11/2013 (StartDate)

Int Weeks = 4

How can i loop from StartDate to Now by number of Weeks(4) and see if the TransactionDate week is equal to the StartDate + Weeks(each loop) week.

Hope that makes sense

Any help would greatly appreciated.

Regards,

Loftty