Render to your desire image size.  Then in photoshop, we are going to intensify the saturation of the colors.  In the actions tab, select either "oil paint" or "soft poserize."  Change the layer setting to "soft light" and adjust the opacity to your desired effect.  Then select your background and create a duplicate layer.  Go to filter --> stylize --> find edges.  Move this layer to the top and set the layer setting to "soft light" and decrease the layer opacity to 10%.