Caveat Emptor -- http://btcinvest.net/en/bitcoin-mining-profit-calculator.php?diff=6978842650&dcosts=4995&diff_mincrease=15&blpbtc=25&dhsmhs=5400000&diff_mincreasedecrease=0.5&btcusd=453.80&dpowcon=2500&btcusd_mincrease=1&pcost=0.115&calcweeks=32&dleadtime=9&action=calc#

This is with modest 15% diff increase (it will be 20% or more).