The main overlay is a small portion of a homemade filter which consists of a generated blue gradient with a lot of grain added to it. That was superimposed on a shot some arty paper I bought at Michael's. I erased some of the filter over the cow and then painted over it in yellow. Nirvana!
This has a really painterly feel to it. I love the colors & the composition. I'm not sure that I wouldn't prefer a little less graininess, but I'm not sure.