Here are a couple of different ideas: a used 24-85mm lens or a 50/1.4. What either would do (especially the 50mm) is to let you shoot at low iso. This would allow you to "zoom" by cropping your 24mp image while maintaining good IQ.
Cropping always reduces IQ, both resolution and noise, and increases DoF.
In many cases, I'll bet you'd get a much nicer result cropping a 100-200 ISO 50mm/1.8 shot than anything at 800+ ISO from a slow zoom lens at, say, 150mm. Unless you're far away, you probably don't need much more than 150mm equivalent anyway.
Let's look at an example where you need 150mm to frame the shot at 1.8m high. You will probably be using f/5.6. If instead you use 50mm at f/1.8 and then crop to the same framing, you will use only 1/9 of the sensor, so only 1/9 of the pixels and 1/9 of the light you captured. That about 3 1/3 stops. So about the same as if you used an aperture of f/5.6 and a 2.6MP sensor So you gained nothing with regard to noise and lost a lot of resolution.
I wouldn't recommend a 50mm f/1.8 unless you could get within about 6m of the stage. Row K won't cut it. for a 50mm.
