VBA Code to detect change in fiscal year between dates

Any good ideas to solve the following problem using VBA? I have a staffing model that goes across fiscal years and I need to recognize when that happens. The user enters 2 dates and I need to populate a table, a column for each week within the date range. I am not sure how to recognize when the fiscal year changes, which is Oct. 1. The dates can span multiple years.

Please help...