Is there a way to get npc sims out of the player's house?

You don't say if she has her own house or not but what I did when my sims gf didn't leave for 3 days was to go to manage worlds, moved her to a different house and then moved her right back home. Then the game will put her in front of her own house. If she isn't "in world" you can put her in somebody's house or her own. Either way, she won't be at your sim's house