I remember those from the 1960s-70s--after that most of them were made from resin. There are a few similar ones listed on ebay, but no exact matches. You might check there occasionally, or put 'worlds best mom figurine' on your notification list (assuming you have an account). Etsy is a good place to look for vintage items, too.

It seems that the sentiment probably means more to you than the actual figurine--the fact that it once belonged to your husband's grandmother is what gives it value. You can glue it together with super glue, then fill in the void with malleable epoxy putty, which hardens, and can then be sanded and painted. Milliput is a good brand that I've used--the smallest size available is about the same price as one of the figurines on ebay.

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Sweetie, my kids are all grown up, but I still have a Hamilton & Jones stoneware jug with a big hole in the side, courtesy of my little ballerina (now 27). I keep that side turned to the wall. ;)