The switch needs to be in series with the lights, which must be in parallel with each other. As for figuring out how much current is drawn, add the wattages of the bulbs together, then divide by the voltage and you'll get current (basic Ohm's Law: Power = Current * Voltage, or Current = Power/Voltage.)

I can draw up a schematic later tonight on how you'd wire this up in case a picture is needed. Tried doing an ASCII-art drawing and it just didn't work.

ME Super