Steve,

I'm in Phoenix also. I have an '05 Gallardo. The coolant that Scottsdale Lamborghini uses is BMW coolant, bluish in color......same as in your car.
I got mine from the BMW dealer for about $19.00 gallon, if I remember correctly. Scottsdale Lamborghini was closed at the time. My overflow reservoir was pretty low also. I used distilled water at first, but then decided on coolant. The manual talks about the blue-colored coolant. I was worried about using Prestone (Yellow/Green) so I called Scottsdale Lamborghini and they told me about the BMW coolant.

Jeff

By the way, what color G do you have?