As far as I understand it your problem is this:

You have sheet1 with the following

Date sales1 sales2 sales3 for cells say a5:d20

You have sheet 2 with the following: for cells say a5:d??

month <sum of sales1 per month <sum of sales2 per month etc

In A5:A7 enter the months 1, 2, and 3

In B5 enter:
=SUMPRODUCT(--((MONTH(Sheet1!$A$5:$A$20)=$A5)*Sheet1!B$5:B$20))

Copy B5 to C5 and D5
Copy B5:D5 to B6 to D7

In A9 enter Q1
In B9 enter =sum(B5:B7) and copy to C5 and D5

Repeat this for the rest of the months

Hans