You can make one pretty easy, I have done this in the past with my WRX, different car same idea though.
Here is some of the stuff I used.
Pep Boys special:
Coolent overflow tank about 15 or 20 bux. (the one I bought had a mounting rack included)
Hose about 10 feet should be more then enugh, better to have to much than to little.
Windshield washer pump, any kind will do here think I spent about 15 bux.
One one / off swicth, you may want to use a momentary kind so you can just hold it down to spray then go.
Some small gauge wire to run to the pump and switch.
As for the spray heads you can pick some up at a garden center. I used the misters on the STI system. I got them from the Subaru dealer parts center.
I cant tell you were to mount the stuff as I did this on a WRX.
But here is what you do.
Find a place to mount the water resevoir, pump, spray heads and switch (switch gose inside the car...duh)
Next run a hose from the resevoir to the pump, then from the pump to the spray heads. You can use a Y spitter to split off to both spray heads.
Wire the pump to the batt. and then to the switch inside the car.
I would probaly look to mount the spray heads to the upper part of the opening on the front of the car where the intercooler is.
You could also place the water resevoir in the trunk (this is the stock location on my STI), you will just need more hose and wire.
Sorry this is not in more detail but it is just kind of a rough idea. Once you get in there and look it should be clear where you can place stuff. I think the whole thing cost me about 45bux or so.