I recommend you get your friend to help out. Have him fly it first, since it sounds like he has some experience. Then see if he has the ability to "buddybox" you to teach you to fly it. Other than that, I think it's likely that fixing the elevator direction is only going to make it possible for the plane to crash from a higher altitiude. Please find an isolated location to teach yourself; there's no need to risk injuring others during the very brief time I expect this plane to survive.