Total Monthly Hours from a date range rollup

Hello All,
We are in a scrum agile environment and I working on a spreadsheet that tracks my teams project/stories for each work sprints. The sprints are 2 weeks long (10 work days). The challenge that I am facing is that we have to report the work hours for each performer on a monthly basis. In a month there can be more than 2 sprints with the 3 sprint overlapping between 2 months. The stories for each sprint are estimated for each sprint and in order to get the monthly totals (for 20 work days), the estimates for the sprints overlapping 2 months have to be broken down accordingly to reflect the correct estimate. (i.e. if the sprint runs from 29-Oct-12 to 9-Nov-12, and testing estimates are 30 hrs, the October total should be split accordingly between 3 days for October and the rest 7 for November.

I have attached the sample spreadsheet for your reference. The sprint planning worksheet has the sprint estimates. I have tried looking into SUMPRODUCT and other functions, but with no success. Any help will be greatly appreciated.

Thank you,
VB

This problem can be solved by using Macro Program insted of Function easily.

Yup, I had a feeling, it'll not be straight function, but rather a macro or a VBA code behind the worksheet to perform this.
Any suggestions, how could that be done?