A. Last year's gearbox was ~139:1. I haven't taken this years apart to verify yet.
B. This is a great learning opportunity, learning how to do it yourself is going to be the fastest and most reliable route to your answer. Take it apart and count the teeth.
Stage Gear Ratio = Driven Gear / Driving Gear
Multiply the 4 Stage Gear Ratios of the FP trans to get the overall ratio.
The white paper at
http://www.chiefdelphi.com/media/papers/2284 should provide some guidance for getting the gearboxes apart and such.
C. 0.45 N*m is the torque for stall at 70A, don't plan on having that much torque available for any length of time. You can scale it to the 30A torque by multiplying 0.45 N*m by 30A / 70A. There are numerous white papers on this subject.
D. When you get it figured out, post it back here.