I'm not so sure there is a spell that will sure-fire find your cat. There are ways you could send out a spiritual calling, of sorts, that may coax her back to you. However, some twists of fate are made in iron.
Do you have any of her hair? If yes, you can use this to try and call her back. Set a white taper in your window or door way, with the fur close by. Write down a little phrase, which entreats the cat to return, say it periodically, at times of your own devise. You could, as well, fill her food bowl and sit it next to the candle. On a sheet of paper, write her name three times, fold, write it three more times, and do this once more. Seal the folded paper, and leave it in front of her food bowl.
This is by no means a guarantee, but, it is what I would do if I wanted to entice my stray pet back.
You could also put up wanted posters. Call the local animal shelter/s, and ask them.