Not sure if you pointed that last post at me, but I used only
PS with standard filters.
I used layer-shifting to eliminate those ugly lines. Drawback is, that the image becomes a little blurry, but it wasn't that bad in this case. There was still some distortion which I got rid of with a very slight gaussian blur.
Now it's even more unsharp (still not too bad), but a little trick helps here. Since the background has no important detail, the best bet is to blur it more than the child. By doing so the child appears sharper than it really is

The rest is more or less shifting around curves and some painting (well, the paintwork was done before the bluring, but you get the point

).
I guess that's some very unusual technique and I know it doesn't work always, but I consider myself still a newbie so I think that's ok