Release the code.
You'll get some donations. Nobody with a brain is going to pay you up front to run unaudited mining software.
I tried that before. Never got a penny. (my Protoshares miner is now used by several noirshares pools and i never seen a peny for it in donations).
I can't understand, too. What if sgminer developers started to ask money for bug fixes or new releases?
If you have made something nice because you are clever, share it with the rest. If you won't share it, after a while your 'fix' will be rediscovered by someone else who will share it.
If you want to make money like this, go to work for the fucking M$