I found that any Offroad lighting brackets are hard to come by in the local market. Amazon usually has the best deals with super fast shipping. As far as the wiring goes, it is up to you how you want them to be powered.
You can either power them straight from the battery, or from either your low or high beams. The PIAA should of came with a relay. I have mine wired so when I activate my high beams, it gives power to my switch which turns on the lights. To do this, the switch "HOT" wire should be connected to the HOT from the high beams.
If you want to turn on your lights by just using the switch, then connect the "HOT" line from the switch to a always hot source such as the battery.
As a word of advice, If you are going to do an independant switch, I would suggest connecting the "Hot" line to an ignition source such as tapping into the cigarette "HOT" line underneath the climate controls. This is so if the car is off, it kills power to the lights. I cannot tell you how many times I killed by battery by accidentally leaving the lights on.
I also got tired of having to turn the switch on and off when I wanted to use the lights. It is so much more convenient to wire them to either the high or low beams. Below is a great link on which wire to tap into in the headlights: