@Sam, download the 16F628 sheet and find the prescalervalues.
You can change the values, but you hav change them both (now into the exelsheet 128 and 16)

@John, cut the middle wire of the opto, this is the basic of the opto transistor.
See the picture I draw how to connect to the timerboard.
If you want to use the opto to you board, there must be into the transistorlead a resistor (1 - 10 kOhm) to plus of the batterie.