Please help !!!!! my nan has two types of cancer?

Hi my nan who is 71 got diagnosed with lung cancer 18 months ago. She had 6 courses of chemo and 15 radiotherapy treatments, she accepted the treatment really well and did not lose her hair, she stopped smoking and put two stone on (7st to 9st, 1). Recently though she has been diagnosed with secondary ovary cancer :( the doctor she saw says they are more worried about the lung cancer and that if she was to die of anything it would be the lung cancer which is under control and has shrank from 6cm to 2cm. I am soo worried about her because she has many other health problems. But she has lots of energy and has put weight on and seems more healthier than before which i cannot understand. Anyway i just want to know how long her life expectancy is :o. thankyou for reading and i hope you can answer my question, and if you have any more information which can help please tell me. thankyou xxxxx