Amazing apartment, in a great location (30minute walk into Central Oslo or a super quick trip on the 12 or 15 tram going from Oslo Central station). A lovely café/ bakery, called Kaffebrenneriet, is located opposite the apartment which we would highly recommend for a hot chocolate and pastry.
Our favourite parts of our trip to Oslo were visiting the Holmenkollen Ski Museum (a 30minute ride on the number 1 metro), walking over the Opera house and the Fram Museum (about 30mins on the bus). Equally, we enjoyed walking into Central Oslo from the Aker Brgge, an upper class eating and shopping location.
As students on a budget we managed to find several restaurants that catered to our budget that were also delicious, Punjab Tandoori in Gronland was cheap but we got loads of lovely food. We equally enjoyed the Italian 'Olivia' many of these restaurants are located all over the city. Nord Uchi Thai is also worth a visit if you like Sushi and Thai food, its reasonably priced and on the way into Central Oslo from the apartment.