The tranny is an integral part of the motor. Unless you want to split the cases and remove the tranny gears and replace, the easyest way would be to replace the whole unit. You can purchase the broken parts from Honda and replace, but, not sure of the amount of work involved. If you can get a fairly nice Interstate for 1500-2000, even if you replaced the motor/tranny, you would have a pretty inexpensive ride.
