Hi Pauline, if it's an 18 carat gold ring, which it sounds like it might be, the silver colored metal around the stones is most likely platinum or palladium.
Unfortunately, without an image we haven't a clue which direction to research the marks. Then you have the three stones, What are the stones? What color are they? Are they natural or synthetic? Can you identify them or not? The Gemstone Treatment report, is a free resource, and will help here. The link to the resource can be found in the Jewelry Resources.
