The S&P 500 (INDEXSP:.INX) surged another 0.45% Friday to cap off the index's biggest weekly gain since 2011. Today's rally also took the S&P to its highest levels since 2007. If the first week is any indication 2013 could be a big year for stocks. One catalyst for today's rally was a slightly better-than-expected non-farm payrolls number which economists hope will set the stage for robust job growth in 2013.   The strength in the indices has been especially impressive when you consider that the market's most influential stock Apple (NASDAQ:AAPL)  remains very heavy. AAPL finished the day down 2.8% ...