A lot of smart and sincere people have spent years improving the 3-blade HAWT and PMA, so in the end, you may find it will be the best electricity producer per a given cost of effort and money. That being said...
This has been asked before, and I have also wondered what I might do if I got a property that had an existing wind-pumper. Many small blades will have high torque in a low wind, and low winds are the worst for generating electricity due to low RPM's.
I believe one option that might be useful is slowly raising a weight that trips a ratchet when it reaches the top. The falling weight can then spin a PMA for about a minute or so at a steady RPM. Depending on a lot of different factors, it might be generating for one minute out of ten. If the winds you have could raise a fairly heavy weight because of the ratchet gearing, you might even try attaching an auto differential between the power shaft and the PMA as a 4:1 gear-up to increase the PMA RPM's.
If you want to consider this configuration, I'd recommend starting out with water buckets until you get the weights adjusted for the optimum performance. I would want the complex parts at the bottom, so near the top I would attach a simple horizontal shaft with two pulleys. There would be a single power shaft at the bottom that the middle of the cable wraps around.
One end of the cable has a small weight thats just enough to keep tension on the cable, and the other end has the heaviest weight that the wind-pumper can lift. I would use a very large diameter pulley on the bottom to increase adhesion and reduce slippage. If there was still too mauch slippage, a more complex method would be to use a motorcycle sprocket and a dozen or so motorcycle chains placed in the center of the cable run.
Just a few ideas, best of luck, and have fun!