I don't know the exact name for this style but it looks a lot like a Finger Wave that was popular in the 30's and 40's. The finger wave was used for shorter hair and the Horizontal Pin Curl Wave was used for longer hair. I think the last one is the best if you have long hair and looks the most like the girls picture. There is a technique in the book Vintage Hairstyling by Lauren Rennells that could be useful and almost duplicates the exact look in the picture. The technique is called "pin curl waves" on page 47 and there are step by step pictured instructions. I've included the book and a few sites that may help you with the techniques.
You can use a crimper, I don't like the look personally but it could be helpful or flip a curling iron back and forth down the length of your hair to achieve a similar style.
You can also type in "finger wave tutorial" and "deep wave tutorial" into the search box at YouTube. This is where I learned about finger waves and how to do them. Several thick and sculptured braids in damp hair might help achieve this look as well.
If this isn't what you're looking for then I would take the picture into a local salon and ask them for a name for the style You can use that time to say you are price searching and see if they have a great deal. You would get the style done and know the name for future reference.
It's very pretty and I wish you luck with your hair and the wedding. Have a blast!
Next day: I was looking for a medieval style for my hair and ran across this....which is exactly what you're looking for. Hahaha, what are the odds?
*Vintage Hairstyling by Lauren Rennells. Publisher HRST Books 2009. ISBN-13: 978-0-9816639-1-3
*www.thefedoralounge.com search in beauty and style for Pin curl threads