Yes, you can put an inverter before, and also can get a much larger swing with an increased supply voltage in place of +5V.
In other applications where you do not need voltage amplification but need more current driving capability, you can also use the ckt posted by Borber [cscs.gif] with little changes:
Remove R2 and Q1, connect other end of the input resistor R1 directly to the shorted base junction of Q2 & Q3.
But in this case the out put swing is lower and governed by input voltage swing, loading at out put, beta and Vbe drops of transistors [you will get an out put swing of decreased by ~1.6V].
In you present case since you have 3.3 Volt input swing, the out put will be about +0.8 V for 0V input and about +2.5V for 3.3V input.