You know, if I were to paint an R2--and this is just hypothetical, mind you--I would order a brand of paint called Shimrin Kolors from House of Kolor, located at 2521 27th Avenue South, Minneapolis, MN 55406 (800 328 5139). I think I might order Pavo Purple, Zenith Gold and Orion Silver as basecoats, mixing them with a ratio of 50% purple, 25% Gold and 25% silver. I then might coat it with Kandy Oriental Blue, and probably wouldn't put a clear coat on it, though it would add some more depth. I'd guess that a quart of the basecoats each cost about $26.55 and the top coat about $31.49 per quart. Of course, I would have to buy a quart of catalyst at $35.40 and a quart or two of reducer at about $9.80 per quart. I bet if I did all that, I'd have a color that's pretty close to the real color.
For the white color, your best bet is paint code LS015K from Dupont in the U.S. It should have a bit of a sheen to it, so a clear coat helps a great deal. But the most important step would be to dirty it down--even when clean, R2 has a "dirt under the fingernails" look. A water based/acrylic paint, such as Burnt Sienna or Raw Umber brushed on, then wiped off helps give him his "lived in" look.