Overstayed for over a year. I want to go home.

I have been living in china for a little over a year. I came with a tourist visa, I haven't worked while here I have just spent my money and have only been making friends and enjoying my time in this new world. I have a wealthy friend here in PRC that gave me a place to live and would give me extra spending cash. I want to return home now but don't know what will happen to me.
Let me know if I have this correct.
1. I will pay a fine of 10,000 rmb or placed in jail for 15-30 days.
2. Get a black mark on my passport that will remain for 2 years.

I will need a plane ticket to leave the country and return home. Should I buy one ahead of time and go to the immigration department the day of or before my flight?
Will they give me time to get my stuff together and then fly out before a specific date or will they try and ship me out that very moment.

I know that I should have just fixed my L type when I had the chance but it's far to late to be thinking of the "if only I had."

I'm really nervous about how to handle all of this.
Any advice will help.
thanks