After I got it isolated, I've done some retouching work on the base stones, to get rid of the vegetation on both sides
step 3 of 9
I choose a background, by using a circle color gradation
step 4 of 9
Then I've rotated and scaled the arch to get a spiral shape (here are just a few steps, I've done this about 10 times...)
step 5 of 9
For the light at the very end of the spiral, I've used a simple round soft brush.
step 6 of 9
...I've also added some light stars: Make an oval with the selection tool. Then take a big soft brush an put just 1 strike in the middle.
step 7 of 9
Copy this, rotate and scale to make a star.
step 8 of 9
Finally, to enhance a bit my light, I've added a Light-effect (Halo) on a black filled layer. I turned the layer to "Lightened color", and centered it along with my soft brush strike and the light star...