Are you wanting her to brood the eggs for you? Usually once a hen has laid her egg she will immediately lose interest, and go out to get something to eat and drink. Once she goes broody, that is the only time she will be interested in sitting in the nest and collecting a clutch of eggs.
When you say she is breaking them, what kind of material do you have in the nest box? Is it possible the egg is breaking when it is laid because it is landing on a hard surface? The other possibility is that the shells are weak. What kind of feed is she eating and does she have a source of supplemental calcium?
There are many reasons a hen will stop laying, including molting, age, illness, parasites or poor nutrition. Without more information about her, it would be difficult to guess why she hasn't laid for the last 3 months.