I had a great stay at olga's place! The appartment is in the middle of a nice neighbourhood in the citycentre, with a lot of restaurants and bars. You can walk to almost every 'must see' in madrid. You have a private bathroom you can use. Olga and her flatmate are really friendly! They help you with nice places to go to. They also invited me for lunch and dinner.
The only thing is that the bed isn't very big, so if you aren't a couple, you sleep very very cosy together. Especially when you are two dutch tall girsl ;) but i think if you will talk with Olga about this she will look for a solution for it (there is for example a sleepingsofa in the livingroom).