High mileage lease, should I buy it now?

Hello, I have a 2012 Nissan Sentra SE with 70K miles on it. It is a 39 month lease that only allows 12K per year and I still have 20 months left on it, so basially I'm in a jam. When I leased the car I had no money and needed the cheapest option possible and that I would worry about the miles later, so now it's time to worry about the miles. I will very easily have 120K on this car at the end of the lease, which if I had to write a check for the miles it would be more than the buyout price of the car.

My payment right now is $258 and the buyout is around 12K (sucks).

What is my best option? Or please suggest a better one..........

1. Negotiate a price for the car now and just buy it out. I figure if I'm going to have to buy the car, might as well buy it now while I might still have a little bit of negotiating power. If I do this, would it be unheard of to pay less than the buy out price, even with all those payments left? Some combination of?

2. Finish out the lease and buy the car at the end? At this point i'll have a car with 120K miles on it and no negotiating power, since if I don't buy it I would have to pay all those miles back (more than the price of the buyout probably)

3. Return this car early and buy something else? I'll still take a hit on the miles though, because I already have 70K. Those miles will reflect in my new car payment.

What should I do? Is there an option I am missing?

Thanks!!!!