This one is filed under "Dragons - Personnel: How do you fire the indispensable person in your organization?" Question: I have one NAZI fem, the HR director, who is causing problems for the whole organization with her attitude and approach.
Even though she is indispensable to my company, she is my biggest mistake.
How do I rid myself of her since no one else knows what she knows in so many very critical areas? Answer: With regard to Der Führer, my intuition is that you will fire her.
That will be the probable bottom line.
How much more time and energy do you want to allow her to waste for you and the whole company between now and the fire date? To get there more quickly without critical problems, you might want to consider some, or all, of the following:

• Before you start anything, drive defensively...
  assume sabotage.
  (Just because you're paranoid, doesn't mean they aren't out to get you.
  ) Back up all her computer files, etc.
  especially since she runs HR...
  
• Get her to give you a detailed action list of all the items she sees as important that need to be done for the next 3 to 6 months.
  This is a good idea anyway...
  since it should show:
  • Action Item issue
  • Priority
  • Start date
  • Due date
  • Functional area (Personnel, Insurance, workers' comp review, etc.
    )
  • Expected cost if any...
    other resources required
  • I personally like having folks do this in Excel since the columns can be easily sorted

By making sure this is an all inclusive list, you will know what loose ends need to be covered if she quits or you fire her on the spot.
Besides the paranoid motivation, I find having these written action items from ALL first reports to be a great idea.
I do this with a lot of my clients and they very often respond that they have gained immense clarity without getting bogged down with micro-management.
Even though your first reports will moan about having to do yet another report, many, if not most, will use it as a way to show how busy they are...
how important and indispensable they are...
and that they deserve a raise! If you have all your first reports do this, then Der Führer will see no red flags.
Besides, this is a natural since it is both a new year AND new office space! Give her a chance to solve the problem(s)...
this is my usual approach with first reports...
but it requires total candor...
in writing...
and a 90 day performance plan...
with major candid reviews every 30 days.

• Write down every objection you have to what she does or how she does it.
  
• Write down why you see the current approach as a problem or a negative impact.
  
• Write down what you want to see as SOP for each item, including the exact attitude.
  
• Make clear that is what you require for the corporate culture you INSIST on for YOUR company.
  
• Don't mince words on any of the above...
  but keep it objective.
  
• Ask her if she can make the changes to match the culture you insist on.
  
• If she says no, decision made.
  Objectively.
  
• If she says yes, she will make commitments and promises to change.
  (N.
  B.
  : She may or may not even be able to change.
  )
• Monitor, manage, critique and review once a week or every two weeks or once a month...
  whatever makes sense for your organization.
  

If there is genuine improvement...
keep on with the monitor, manage, critique and review until you can check this issue off your list.
If there is no genuine, substantive improvement, fire her.
That means her last day is THAT day.
I've learned, way too many times, when you fire someone, you do not keep them around for even a day! Not even until the end of that day! Consider, for your sized organization, outsourcing the whole thing...
it may be cheaper and give you even better coverage for all the things that go into HR these days! If nothing else, outsource in the interim so that you don't feel rushed hiring the right replacement.