Even if you were able to rent points from Wyndham (I don't know the policy for Discovery members), renting 80,000 points would cost you $960 (at $12 x 80). Your best bet might to book what you can with the points you have, and find another owner willing to rent you a reservation for the remaining nights you want, ideally in the same unit type. Many resorts will work with you to stay in the same unit upon request.