Hi Danielle, unfortunately it's not that simple to get the value for those rings, mi advice to you is to see a jeweler or two and ask them what value they have. You can try visiting a few antiques shops as well.
Danielle, I would recommend showing your rings to a professional. First, it's very difficult to assess jewelry based on digital images (which can be distorted on the screen), and second, when you decide to auction the rings, customers would want to see details of professional appraisal, perhaps some documentation, or reference -- keeping things transparent will leave the buyer happy and increase your authority standing as a seller.
I agree with the previous answers. I would absolutely have a professional check them out. You also may try contacting Tiffany & CO. I'm sure they would definitely be able to help you with an appraisal.
I agree with Elijah. If you are planning to sell them at auction go to a reputable house and they can tell you what you have and the estimated value. They will tell you initially if they are interested from a photograph...some will charge for an appraisal, some not...ask before you go.