Bad luck, Rose. Peter is right about using file recovery software and, as Google will tell you, there are quite a few out there. I have not checked, but having a demo version which tells you what files can be recovered and giving the option of paying for the software if you want to proceed seems to be the way this particular market works. Sandisk provides a licence with its more expensive cards, so possibly you have what you need already. And if one company's software does not work, then someone else's might.
Also, do not even think about using the card again as there is a risk that you will get another corruption. These days they are cheap enough to bin a dud and purchase another. 7DayShop is reliable and usually has competitive prices, as many retail shops seem to charge considerable premiums. Possibly you can save a bit of money by going for one which comes with file recovery software included.
http://www.7dayshop.com/It might be an old fisherman's wive's tale, but a while back I read that one way to reduce the risk of corruption is never to delete files from the card, either in camera or on the computer. When you are ready to reuse a card, simply reformat it in the camera. As I say, I don't know if there is anything in it, but it is what I do. So far, I have only had one SD card go AWOL, but maybe I have just been lucky.