Sumif or Index/Match on Multiple Criteria including Dates to Month?

I tried to use the Index and Match functions, but I think I should be combining a SumIf function somewhere. Unfortunately I haven't been able to make it work.

I have a table of Client Managers, their Annual Pipeline Amount per deal, and a Transaction Date (Sheet 2 - which will be continuously updated each month).

I need to sum the Pipeline Amount from that report by Client Manager Name and Month on the summary tab (Sheet 1).

You can see for John Smith under Jan 2015, it is showing $300,000, when it should be showing $600,000 (see attached file)

What formula should I be using?

Thanks a lot!
Patrick

Thank you both! It works great! I just clicked "Add Reputation" for both of you! I really appreciate it!