Tragiccomedy from my game

Here, Italian tournament round 2, I play EvansGambit. At move 10, Black hangs his g7 pawn, I grab it next move. Black thinks to save his rook by exchanging Queens. I give a thought here. I want to win his rook. I have 2 candidate moves, the first one which came to mind would win me a rook and a pawn for my bishop. The second one, i thought will win me rook without giving my bishop. 

Here is the position from the game

I choose 2nd option, and my opponent resigns. Why did he resign? What did we miss. Go to the link to find out.

A commedy of error, we both miss simple move. but i win. A game to remember not because of my win, but because of my error