Mining bitcoins depends on your hardware (asics) and luck. According to alloscomp (https://alloscomp.com/bitcoin/calculator), You would mine 1.0000 BTC with 3051.999 GH/s, with difficulty factor of 46717549644.7; That's an approximation, if the difficulty goes up you might need more hashing power, if it goes down you might earn more than 1 BTC.

Antminer S5 seems to be cheaper and a secure asic, unless you have nearly free electricity, you wont ROI (return of investment)