Tried with gradient maps and color ranges but it didn't work.
View attachment 1354387
This was much easier. Created the lighting in Daz, and simply had to match it on the neon-like-elliptical-thingy.
Far from perfect but good enough considering it's literally the 2nd time I'm even attempting doing postwork. The image you referenced was the first. What I do not like with this workflow is the attention to details and all the work I'd need to make it proper as opposed to just flat out rendering the damn thing. And there's a LOT of details I should fix here before I'm feeling good about it.
Hair shine for example, eye reflections, the legs look like they're clipping and so on and so forth. But I DO like the hazy look it gives. Iray wouldn't do such a good job if that was a prop light, nor would I be able to have a color gradient in the light.