All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad is His slave and Messenger.
This woman is obliged to make up for the days during which she broke the fast during Ramadhaan before the next Ramadhaan starts.
If she has a valid excuse, such as a continuous illness that allows her to delay making up for the fast which she had broken, then she is not sinful for delaying it.
However, work is not a valid excuse for delaying making up for the broken fast, as she could have taken a few days off until she makes up for the missed fast that she is obliged to make up for. So if she delayed making up for the fast without a valid reason, then she has to make up for those days in addition to paying a Fidyah (expiation) for each day. The expiation is to feed one poor person for each day of which she delayed making up for the fast. The food for each day is about 1.5 kg of rice.
If Ramadhaan starts, then she must fast, unless she has a valid excuse that makes it permissible for her to break the fast, such as an illness that increases by fasting, or if fasting delays the recovery from the illness.
For more benefit, please refer to fatwas 5978and 101245.
Allah knows best.