Ellen is a very kind person, willing to help you in anything. Her house is very organized and she has everything you need to make you feel comfortable.
Near her house there is a subway stop (number 70), and a train stop (Ryen). Both take you straight to Olso town.
To get to her apartment from the airport you have to take the train from the airport to Olso station, then take bus number 70.
If you want to eat, there are at least two supermarkets near her house. Something important, you have to be prepared to spend money on food because life is a bit expensive.
I highly recommend the place for short-term stays. Since the city and tourist places can be visited in just one week. And if you want to stay longer, you may feel somewhat bored.