As this has been quite a long thread perhaps I could list the practical options that have been suggested so far:
(1) Gear up the existing motor so that it spins faster and produces more output voltage and current post (Post #9)
(2) Select a different generator (motor) that has a better output voltage and current at the same rotational speed as the turbine (Post #9)
(3) Use a moving coil meter with a resistive load to indicate output power (Post #85)
(4) Use energy harvesting techniques to generate 5V from the existing generator (motor) (Post#7, #8, #26), and illuminate a high efficiency LED (Post #121)
spec