Just wait out till PSN is back, I guess it will be back under a week (lol I hope actually)
Buy some good single player game for PS3 till then , or borrow from a friend so that u don't lose money and you can keep yourself busy until PSN is back.
Buying Xbox at this time might turn out a waste of $200 + Xbox live subscription like $50 + a game 50$ so it is gonna cost you 300$+ and I'm pretty sure you will go back to PS3 when the PSN is back so why pay $300+ just for a few days, instead get a good single player game for PS3 or just play some free MMO on the PC till PSN is back .
Hope I helped