Tell us about yourself!
The circuit remains on even if it is emitting no light. Consider using a 5v arduino power source.
Play around with the resistors. You can probably replace the 1k with a 500ohm. Don't know for sure though
Use a 2n2222. Almost any PNP will work.
Only reason I replied is because I stumbled across this tutorial while searching for a nightlight tutorial for a friend. Cheers.