Auto Incrementing Ranges

In order to retrieve my Q/Q QTD % (Quarter over Quarter Quarter-to-date growth) accumulation, I need to have an incrementing range. They stretch across the page coumns and I would like my QTD to automatically update the ranges. Below is an example table.
A B C D E F G
1 W1 W2 W3 W4 W5 W6 etc. Q/Q
2 FY06 5 4 6 4 6 5
3 FY07 6 7 5 4 =sum(B3:E3)/sum(B2:E2)-1

As the Weeks are filled, I would like to move from column E to column F with some efficient function. I began creating a user-defined function, but got hung-up when VBasic didn't accept Moduluses (my columns extend past Z). I'm perfectly willing to use natural named ranges as well, I just can't figure out how to get it to work just yet. Any and all assistance would be appreciated. Thank you.


Part of the user-defined function I was attempting:
=IF(COLUMN(E3)-1>25,CHAR(64+INT((COLUMN(E3)-1)/26))&CHAR(64+MOD(COLUMN(E3)-1,26)+1),CHAR(64+MOD(COLUMN(E3)-1,26)+1))