Entering New Weekly Data causes Summary Page to Update..How?

Here is the situation:

I have three sheets in my excel file. Summary, Company A, and Company B.

Each week, I need to add the sales figures for Company A and Company B on their respective sheets. The sheets would be set up with Week 1 in Column A and Sales # in Column B. When a new week arrives, I enter the new sales figures under Week 2.

The summary page lists Company A and Company B and their respective sales figures with a total at the bottom.

I would like the Summary page to automatically display the Sales Figures for the last week that I have entered directly on each Company's page.

For example,

Company A
Week 1
11,000

This would be displayed on the company's sheet and also on the Summary sheet.

When I add the Week 2 sales figure under this on the company's sheet, I want the Summary page to display this updated total instead.

Any ideas?

DrSues02

No ideas? It seems like this wouldn't be too hard to implement I just don't know how to do it.