semerson:
... automatic gain control amplifiers, I assume this IC's advertised automatic level control is the same thing?
Same-ish. Automatic level control, as used in the datasheet, implies that the output will be within a vary narrow range.
"...voltage input range of 1000." Do you mean over a range of 1000dB, 1000V, 1000x, or what?
A range of 1000x. If the datasheet's claims are accurate, you should be able to design a circuit with that will deliver a constant AC voltage at the output while the input signal varies by a factor of 1000.
I have drawn a schematic based on the diagram in the data sheet and attached. Does it look correct?
I don't know. I'm not an expert in using the SA575. I have an application for this IC myself, and I was hoping that you'd design and debug something, and then tell me how to use it. I think that you're in for some experimentation. My suggestion is to implement the circuit shown in the datasheet, and see how it performs. Armed with that information, you'll be able to calculate how to manage the IC's output to use it as input to something else.
I'd recommend considering the output voltage of your amp to be more like sqrt(2) * sqrt(50*6), and then add a safety factor, and then protect your inputs to avoid damage from overvoltage. The output power quoted for the amplifier is probably imprecise, and it's based on calculations that might be different from the ones that you and I would make. After you know more, then you can hook it up to the next delicate circuit.