I really do feel for you, but you are an example of exactly why I always advise consumers to never get involved with a rent to own arrangement.
There are so many risks, and the biggest is your loss of whatever deposit you gave and the extra rent you are paying, as all of that is non-refundable.
I doubt very much the seller will allow you to find a new buyer for the home as your agreement is with him.....and he can hold you to it.
You say your credit is "awful" - I would imagine it was as awful when you entered into this arrangement......and, whoever encouraged you to do this didn't have your best interests in mind.
To anyone who is reading this, if you do not qualify for a loan now, RENT in the normal manner while working on your credit or whatever it is that is keeping you from buying a home in the normal way.
Justus, I feel sorry for the position you are in.
My only suggestion is to speak to a mortgage rep and see if there is anyway you can get your finances in order by February........but if the seller is falling behind on his own payments, that's a bad situation.
As far as the owner not paying his taxes.........well, that's another pitfall of this kind of arrangement. You have no control over what the owner is or isn't paying....some also fall behind on their mortgage payments.
You see, most sellers who want to sell and CAN sell, sell now, not later.
Not sure it will help, but you might want to speak to a real estate attorney, of course, you should have talked to one before signing this contract.
If the seller is not maintaining the home, it might be grounds for you to cancel your contract and move out sooner... into a home for less rent. Seek legal advice.