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If you were married to the woman at the time you gave her the 2nd ring it is a gift which she may do whatever she wants with. If you were not married/divorced at the time you gave her the ring you should file a conplaint in court to get the ring back. You should do this quickly because you may lose your right to it if she sells it. The engagement ring for an umarried male is given in exchange for a promise of marriage, where the marriage does not ocur the ring should be returned.
Please be aware that my answer is not legal advice, it is merely information and no attorney client relationship has been formed. You should always contact a local attorney for legal advice.
You can recover the money if she still has any. The ring however would likely be considered the property of the new owner who would be deemed a "bona fide purchaser for value" and entitled to keep it. If she GAVE the ring away you could probably get it back.