It sounds like the linkage is off from the outside door handle. There are two ways you can open this door. First Unlock the door.
1. You can stick a slim jim or a coat hanger (available to the public) into the door of the back door to catch the lock rod (linkage). Once you catch it pull up and the door will open. If you have access to locksmith car opening tools they work better.
2. This takes patience. Open the passenger rear door. Notice where the child safety lock switch is. Get a good mental picture as you will attempt to disable the driver's rear door blind. You will stick a piece of wire, or plastic into the side of the door and attempt to locate the child lock. It CAN be disabled with the door closed.
Once you have the door open, go ahead and remove the panel and re-connect the linkage. This will fix your problems.