YOu are saying the engine kept running and the power steering was very tough to turn, and you couldn't manage to get the car over 25mph, correct?
What noises precluded this and what noises came afterwards?
Did the coolant temperature spike quickly or enter the red area of the gauge?
Did the Autozone guy do a scan of codes on your car, is that why they told you thermostat/fans? The fans are relatively easy to check, turn the AC to on. This should turn the fans on.
Since you have odd smells and other issues, you may want to seek a real mechanic as we won't be able to see/smell and honestly diagnose your car properly, if the belt(*) is still on and in place.
00 Regal GS: All kinds of cool stuff.