Will the repetition will always match the current dates day of the week?
Set Field [Table::RepeatingFieldName[DayOfWeek ( Get ( CurrentDate ) ) ] ; Get ( CurrentTime ) ]
With Set Field selected for your script, press the upper specify button and select your repeating time field. You'll see that name in place of the Table::RepeatingFieldName part of my example. Then enter the DayofWeek calculation into the repetition box at the bottom of this dialog. Click OK. Now click the second specify button and enter the text to the right of the semicolon (;).