0 - 2 of 2 tags for week

Dear All
I have stored information about company sales in a table tab_sales as follows:
Company Week         Date                 Sales
Co. 1        201237      10-09-12           $200
Co. 1        201237      12-09-12           $150
Co. 1        201237      14-09-12           $420

I need to rollup and report data by week, with the week being defined as Sun through Saturday and identified as the Saturday-date. Does Teradata SQL have any functions that could facilitate this?