You might want to buy a more suitable multimeter. My 20+ year old Fluke 83 has AC ranges of 0.4, 4, 40, 400, and 1000 V -- and I find I use all of them a lot.
Also note that your measurement accuracy will probably be substantially less than the DC measurement accuracy the marketers love to stick in your brain. Typical multimeters have AC accuracies of 1% to 3% or even worse. The composite measurement might have e.g. a 5% measurement accuracy. You might also need to worry if the current waveform you're measuring is not sinusoidal -- even if the meter is an RMS meter, check the bandwidth, as the cheap meters have cheap bandwidths.