I would find records and then sort the results so that the next or last interview date sorts to the top of the found set. That approach will work even if unusual circumstances require an interview on a day other than Monday or Friday.
Here's a script for finding the Previous Interview Date:
Enter Find Mode
Set field [YourTable::InterviewDate ; "< " & Get ( CurrentDate ) ]
Set Error Capture [on]
Perform Find 
Sort Records [no dialog; Restore] //Sort your records in Descending order based on InterviewDate
Go To record [first]
A similar script will find the next interview date, but use > as your operator and sort your records in ascending order.
IF you need to, once you've found and sorted these records, you can use the data in the first record to perform a second find that constrains your found set to just records with that interview date.
THANKS! Looks so simple in retrospect. I will try it and report back.