The protagonist's main purpose is to be able to express herself as an American, due to the fact that she now lives in the United States. We learn that she is very happy to be able to express herself properly in this way when she says: "When I was done, I read over my words, and my eyes filled. I finally sounded like myself in English!" However, the protagonist also wants us to learn how her family's past has impacted their views, and the deep connection that she feels with her mother. This is obvious when the protagonists says that her mother tried to make her feel better after her fight with her father. We also learn that her mother was very supportive:
"“Go away,” I wailed, but we both knew I was glad she was there, and I needed only a moment’s protest to save face before opening that door.
The themes of "Rules of the Game" are all about conflict—first the eternal conflict between generations, then the equally well-established yet less clear-cut conflict between authority and intelligence. There is also the more equal and cerebral conflict involved in a game of chess.
The answer is hyperbole. It is very unlikely that there was absolutely no money, absolutely nothing to buy, and absolutely nowhere to go. A hyperbole is a gross exaggeration, meaning that what is being said has been expanded to prove a point.