The solo mining comments are correct. It is nearly impossible to make anything mining alone, this is why people join pools, to find and mine blocks together.
Determining ROI is easy, just use a calculator. For instance;
http://www.coinwarz.com/calculators/bitcoin-mining-calculatorJust plug in your chosen pools fees and your chosen miner's stats in GH/s or TH/s.
Pool? I suggest Slush's pool, Elugius and Antpool are known to steal blocks from their miners and I haven't recognised Slush's doing it. Your pool is your choice though.
Hope this helps!
