Runtime w/ Bad alternator (pulley?)

I have come looking experienced knowledge more than a diagnose issue.

I can't get into a mechanic until next week. My car's battery light came on and SGII said I have 11.6 - 11.8v. Changes in speed and rpm didn't change the values. After a 40min ride @ 115kmh the voltage was at steady 11.5v.

My Diags:
Battery charged to 13.8v with battery charger.
Battery tests fine using a "chinese" battery load tester ($50).
I have heard a couple "squawks" (maybe 3 or 4) with the belt when wet outside (I assumed serpentine belt).
I replaced idler and tensioner (and serp belt) about 20,000km ago.
I assume I have a bad alternator pulley from what I have read.

Question:
Should I replace the alternator completely, or just the pulley?
Think the alternator will last me a 6 more trips of 250km roud trips? (if I keep recharging battery, or would this help?)

The car has 470,000km (295,000miles)...should I at least try just the pulley?

Just to give an update, it was the alternator that gave way, the pulley was still good after 470,000km...replaced with a Bosch rebuilt and all is good.