Are you trying to create columns of data by week, i.e., do you want to show each week of n number of weeks going across with corresponding data below each heading? If so, you could try inserting a crosstab with your date field as the column. Then click on the datefield and choose "Group Options" and choose "column will be printed for each week."
If this is the format you want, but the crosstab doesn't have enough flexibility for your needs, you could also create a manual crosstab to get your detail fields by creating formulas like:
if {table.date} in Date(2003, 05, 18) to Date(2003, 05, 24) then {table.amt}
if {table.date} in Date(2003, 05, 25) to Date(2003, 06, 01) then {table.amt}
-LB