I too am a very happy QL17 GIII user. I'm going to b slightly contraversial however, and suggest that you ignore the battery problem entirely, here's why:
The meter is only coupled when the camera is in automatic mode. The automatic mode on the camera is called "shutter priority." What this means is that you select the shutter speed and then the camera will decide what aperture (f stop) is necessary for correct exposure.
For street shooting, shutter priority is pretty hopeless; though aperture priority would not be. The aperture controls the depth of field (how much of the picture, from the selected focus point is in focus.) If the camera had aperture priority, the meter would be a bunch more useful but as it is, you find youself switching between A and manual (the other way is to twist the shutter ring until it reads the f stop you want). However, the lack of exposure compensation makes life still more awkward.
I use my camera without a battery. I have a Sekonic L308 meter - though, if you are shooting B&W, practice and a copy of the "Sunny 16" rules, though harder, will be more rewarding as you learn to read light properly rather than relying on a meter. At first this is a burden, with time, you become liberated from metering and more able to concentrate on making the picture you want to take rather than worrying about how to get *a* picture exposed correctly.
HTH
charly