Now use the Clone tool and also paste in new elements to hide the join in the centre. You will then need to merge all visible layers. Make sure, however, that you keep the background transparent.
Now we’re going to stretch the image to make a square, go to Image > Image Size and distort your image to make the pixel height and width the same. Make sure you have constrain proportions clicked off so it will distort your image. Flip your image vertically by going to Image > Rotate Canvas > Flip Vertically. Now go to Filter > Distort Polar Coordinates, and then click Rectangular To Polar to get your desired polar effect.
Now cut-&-paste this layer into your master document just above the background, and you should get a halo of urbanicity around the model’s head. Place this where you want to fit within your composition.