Transistors with different loads in parallel
Ground the emitter of Q2, and take the signal from its collector.  Leave R2 there, but increase its value to 3 - 5K.  This will invert the signal, but that is easily fixed in software.

You should probably have 1K or so resistors between Q1 base and Q3 emitter, and between Q2 base and Q3 emitter, to make Q1 and Q2 a bit more independent of each other.

As you show it, Q2 is used as an emitter follower, so its emitter can never be higher than about 0.7 volts below its base - and its base is held at about 0.7 volts by Q1's emitter/base junction.