You ordered 12 GPUs for mining and don't even know how to calculate how/if you will make a return.... That is sad.

Here is a great calculator that I use:

http://karldiab.com/EthereumMiningCalculator/

It pulls all of the latest difficulty, network hashrate, price etc etc automatically so all you have to do is input the MHs on the very top line and it does the rest.

Hope this helps.