RE: how long would it take to fix this damage?
I would say keep it for later. Get another trainer but dont toss this one yet.
After you get decent at flying, take this avistar and turn it into a canard. I did it with my trainer after I got bored of it and moved on to other aircraft. Just cut off the nose completely and make a new fire wall(because the CG needs to be ahead of the wing so getting the engine as far forward is good). Flip the whole fuse over and make it a low wing plane. Then take the rudder and mount it on the back and flip the elevators backward. Get all the right connections and you have yourself a canard.
I loved my Canard. I called it the Hammerhead because I had to put a hammerhead in the front to get the CG right but the plane was wonderful. Is was too bad that I planted it only after a few flights due to the hammerhead coming loose during flight. I lost control and it had a most spectacular crash.