ok so I got my sims agents and then i found my sims kingdom so what should i do buy the game or not

so here is my situation I want the xbox 360 but I already have a wii ( got it for chirstmas and i hate the system cause i'm the only one that buys games in the family and im not buying them on this and it is slow and not much fun , if you like a game on it comment and tell me what game i should get) and a ps2 ( i like it but i want something new ) so i have the money but my dad says " i don't want a third game system " what can i say to convince him? jedisouljia