New Landscape Lighting Questions

So we are looking to add low voltage landscape lighting to our house. By the front door of the house there is already a switch for the outside porch lights. The lights are under a roof however. I know I am not supposed to have more than one circuit within a switch box but I'd like the switch for the transformer to be in the same box as the existing switch. What I am wondering is what I can do to make that happen.



My first thought is to convert the existing circuit to a GFCI circuit and just add in a run from the switch box to the outdoor transformer. The other idea would be to put the transformer inside the house and just run the low voltage to the outside. Any ideas would be greatly appreciated.



Thanks!

New Landscape Lighting Questions