Basic electric/wiring questions resources
If you have to ask about basic wiring, the answer will be to avoid mains power wherever possible. So you're looking for a 12V power supply that can supply both the motor and the lamp - say, a 12V 50W supply (4 Amps - a bit more like 5-6 amps won't hurt.

So keep everything else 12V - and add some form of short circuit protection in case anything goes wrong - the supply may have short circuit protection but a fuseholder (5A fuse) in line next to it would be a good idea too.

40W bulbs are usually 110/220V - however similar powered bulbs are certainly available for 12V, as are LED bulbs.- ask any auto parts place. 

While you're there, ask about the fuseholder, spade clips and a crimp tool (often available as a kit) - this will make the wiring simpler, the spade clips will plug onto fuseholder, switches and lamp bulb holder for easy assembly and changes.