My point was that you could set up a lookup table with the weeknumber and the schedule that applies.

It would have 53 rows (53 would be same as 1) with 1-53 on the left, and your schedule to the right (could be 3 columns of schedules, just alter the vlookup)

Your VLOOKUP would have something like

=VLOOKUP(weeknum(cellwithdate),LookupTable,2,0)
and could be copied down your cells where you want to return the schedule...