Indeed, the pins can't measure over 3.3V, even though they're able to tolerate being driven up to 5V. The 5V tolerance is only for being able to receive 5V digital signals.
However, the 3.3V analog input range is when using 3.3V power as the reference voltage, which is the default setting. A 3.3V power reference makes sense when measuring voltage from a pot or resistor-thermistor or something else that scales when/if the power supply voltage changes.
If you're measuring an external voltage, which is independent of the 3.3V power, you should really use the 1.2V internal reference. It's far more stable and has virtually no change when the 3.3V power changes slightly. You'll need to reduce the 8.2K resistor to get the right 1.2V scale, but eliminating error from fluctuations in the 3.3V is almost certainly worth it.