It doesn't actually look all that worn, mine was way worse when it stopped working.....almost no brushes left at all. Your alternator itself may have failed, or the regulator may have simply gone bad. Obviously the first thing to do would be swap in a new regulator....$107 is WAY steep though, online they are only $30ish....you don't have a NAPA or anything near you? A voltage regulator is a fairly common part.....

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