Not sure the answer is in the current rules, actually. Here are some excerpts from the ruleset:
"The game is won by the team who topples all the kubbs in the upfield and on the baseline then topples the king. However, if a team topples the king at any time prior to toppling all field and base kubbs then that team immediately loses the game.
Any rules enforced on the throwing team (including warnings) during any throwing phase will result in a forfeiture of the last toss. Reset game components to the positions prior to the last throw. Kubbs thrown on a forfeited toss are to be removed from play and treated as though they were thrown out of bounds.
Toppled:. A piece that has been struck by another piece as the result of a throw and becomes parallel to the ground. Pieces that fall over due to wind, uneven ground, or being jostled by a player are NOT considered Toppled, and should be placed back in their original position prior to the throw."
My gut says that you lose the baton, the king is stood back up, and you can try again if you have another baton. Since all other kubbs have already been toppled in the scenario question, you wouldn't lose, based on the fist excerpt above.
"if a team topples the king at any time prior to toppling all field and base kubbs"
I would like to hear from USAKubb on a ruling.