I need a formula for:

Sales Report:

A B c d

Item qty Price month

11157 5 1,000 4/2007
11159 4 500 3/2007
11175 1 800 4/2007
11177 2 900 5/2007
11755 10 2,000 4/2007

I want to sum all qty of items sold in april and put it in one column then
due the same for the price. I tried to use sumproduct unfortunately it is
not working. This is the formula I am using.
=sumproduct(--(month(d1:d10)=1),b1:b10)