Something augmented has been made stronger or bigger: an augmented pension has been increased.
Ever read a Popeye comic? When Popeye eats spinach, he gets augmented strength: he's a lot stronger, with bulging cartoon muscles. Anything that is augmented is stronger or bigger in some way. In sports, players are augmented by illegal performance-enhancing drugs. A car can be augmented by customizations. Computers are augmented by adding fancy new programs to them. When something is augmented, it's better than before.