The "help" section at an autozone or O'rielleys usually has lights and switches. And they are usually 12 volt for automotive use.
Led's are pretty interesting, they are rated by several things, but one is the viewing angle. The ones that generally have a very high luminosity, usually have a very narrow viewing angle. It is brighter, but only when looking at it head on. You might take this into account with how you are mounting it. If you can mount it so you are looking straight down into the led, it will appear much brighter.
