create a drop down which allows multiple selection and change content of table based on th

need your help guys...

i am creating a report which should i hope should be as dynamic as i can. in this report i need

a. create a drop down which allows multiple selections (i.e. in week, i can choose 1, 2 3, or all depending on what i click)
b. table will change depening on the combination of the dropdown selected
c. column L in the table will be automatically sorted from highest to lowest

super thanks in advance for your time.