There are many things you can do. You can go to the local junk yard, check out how much it will cost you to buy a used one. You can check the Craigs list for inexpensive transmissions that someone may be selling. You can also call several people in the club to see what they can do for you. Now there is nothing for free in this world except advice!
How much do you love your Jeep will determine your actions to safe it. Like Gill said, this is an expensive sport. What is wrong with the transmission? Be specific. Because not long ago I though the same about mine, through the resources of the club I found a friend to help. It turn out the transmission was fine it just needed to replace a 17.00 dollar part. Yet, had I taken it to a service center they would have clipped me for the same as you; 1500 buck and I would not have been any wiser. Therefore;
get a little patience and research before you act.