Excel 2007 : Multi Conditional Sum

Hi

Try to explain...could do with some help please

I have 2 sum if statements if you like that i need to bring togeather and them calulate a summary of a certain colounm if it matches the criteria.

I have it like this

Col A Col B Col C
Brand Month Revenue

What i need it to do is IF IT = a certain brand AND a certain month then add togeather the revenue from COL C.

Im using this at the moment that adds togeather the revenue from picking up the 'brand'
=SUMIF('Input data'!$A$7:$D$321,"Climate",'Input data'!$AC$7:$AC$321)

But as i said above i need it to pick up the brand, then the month, then add togeather the Revenue any help would be GREAT!!!!!!!!!! thanks very much