How to identify new entries weekly and pull totals from pivot table?

I have a workbook that has 3 worksheets. One is a master list of customers and jobs we have done for them. Another is a pivot table that lists the customer and a count of the number of jobs we have done for them. The last is a sheet with the new weeks data (which will be combined into the master list next week). I want to be able to tell how many new customers we have each week, total customers (ytd), what the percentage of new customers is (total), and what percent of one time customers we have (total). I don't know what the easiest way to do this would be.
please help
Brad