Lighting, Light Fixtures, Ceiling and Exhaust Fans - Power for an outdoor yard light

I want to add an additional outdoor light on a switch above my garage door to better light my basketball hoop in my driveway. I am looking for some suggestions on where to pull the power from and some plans to do it.

The existing light is on a timer which I want to maintain. I have easy access to the power line to the existing light. Additionally, I have an attic above my garage and I have access to the electric lines suppling power to the lights in the garage but they are in series.

Can I add another light to the series with a switch? Or can I pull power from the existing light, add a switch and not affect my existing timer? What is the easiest way? Thanks.

The lights in the garage are in parallel, not in series, but that's terminology. You can't pull power from a switched supply. Do you have access to an unswitched power source, say to a receptacle in the wall? If so, and there is enough slack, you could kill the power, cut the cable, install the two ends as well as your new power run in a junction box, and run it to your light/switch set up.

Thanks for the advice. I do have a receptacle but it already has wire connected to both sides of the device. Can I still get power from there?

Yes, but you can't hook another wire under the screws. You will have to pigtail one of the hot/neutrals and wire nut them together. One screw, one wire.