Just my opinion...not legal advice
Even though some replies to your post indicate that you cannot apply for adjustment of status if you are out of status, I think that is wrong. Even the employment based category gives you 180 days grace period to file adjustment of status based on 245 (k).
After your wife becomes a citizen, you are able to apply for your adjustment of status despite being out of status as long as you were inspected at a port of entry. I'm not sure if this holds true for sponsors that are permanent residents. You should definitely consult a lawyer either way.
As far as your I-20 is concerned...it can indicate an end date of 2020...in order to maintain your status, you must be taking a full course load. As soon as your school finds out that you are out of status, they will terminate you in the sevis system. It would probably have been better to complete your studies, obey the laws of the country you are seeking permanent residency for, and avoid any headaches in the first place.
Good luck.