where to pay penalty when overstay and how much does it cost?

hello there...i"m abby and presently working here in china bit unfortunately my ex-employer didn't get me the visa for the reason that i donot know,and im already 1 year overstayed here and im planning to return home as soon as i have i have enough money to pay for the penalty. I humbly ask your good office where to surrender and how much does it cost the penalty? thanks a lot and looking forward for your response.