adding columns

Hi,
I need to add up 500 pages manually and I would love to find a solution to my problem.

I need to get a total of all the wines and a total of all the beers but they are split into different categories like local beers and imported beers and I have the same for wines. Also an added problem is that there are not always the same type of beers being sold and it means I don't have the same count of rows from week to week as illustrated on my webpage http://www.multiline.com.au/~wje/macro.html .
I thought it would be easier to make a webpage to see what I mean.

I know it is quite a task to find the solution and I am willing to spend all the time necessary to make it work but I would need a bit of help as I am a bit new to this.

Thanks a lot
Andonny