Most silver rings can be straightened by sliding them on a ring mandrel and tapping them with a rawhide mallet. Almost any kind of a large tapered punch will work. After doing it one direction, reverse it and do it from the other way so that it is straight. Two sources of ring mandrels are Thunderbird and Rio Grande, both out of Albuquerque. If it is really smashed and the metal is cracked, it will probably break when you straighten it. Almost any jeweler or silversmith should be able to repair it. Most have to remove any stones before they can be soldered.