Access Active Battler from Window_BattleStatus?

I'm trying to figure out how to access attributes of the current active battler (actors only) so I can post one of their attributes in the the Window_BattleStatus. I don't want to post all four actors' stats, just the current active one.

I've tried a lot of ways, like   

Code: [Select]

@actor = $game_party.actors[actor_index]


and

Code: [Select]

@actor =@active_battler


but I keep getting nil errors.