nemesis:
any resistor from line voltage to a PIC is a no no, you are making the circuit hot. My suggestion is:
If you don't want to use a small rechargeable battery I suggest an AC plug in, bridge rectifier, two resistors to ground (voltage divider, max 5V out), a connection from between resistors to PIC to detect power present. Also after rectifier, two diodes (like 1N4001) to two 78L05 or similar.
AFTER diodes one capacitor to ground for each 78L05, one small (like 470uF) for circuits other then PIC, Receiver etc. and the other a large capacitor for the supply of the PIC, Receiver etc which needs to have power after ac is off.
If you would use a 9V NiMH rechargeable battery you could simply trickle-charge the battery all the time. You would have much more power available for a relatively long time after the power is off and you could run the whole circuit off the battery. I hope this makes sense to you.
Gunther