Personally, If you have it relatively straight i.e. the motor is behind the heli and functioning, I would try to get a little more life out of it. New tailbooms are 16.00 bucks so i'd suspect you wouldn't want to buy to many of these, lol. You can substitute a knitting needle or go to your local archery shop and pick up a arrow shaft and mod it to work also. Either substitute will require some work but from i've read it's pretty simple.

As far as changing the boom you'll need a few simple tools plus a soldering iron to disconnect the wires from the motor and to resolder. The only thing I would really worry about is the little screw under the boom that holds the motor mount on. Do not lose this screw because if you do and substitute it for a different/longer one you run the risk of shorting out the wires and frying your 3-1.