Surprised no one has suggested this idea yet: have you considered offering to buy the company? If the core business is sound and you think you could run it better if you were the boss, consider offering to buy her out!
You could structure it a number of ways where you might not have to pay a lot out of our pocket. If the company has revenue you could probably get a loan, too.
Your bargaining power is pretty high. If she doesn't want to sell the company to you, and you walk away, she gets nothing, the company goes under, and you can just go get another job or startup your own company on the side.
I recommend the book Getting to Yes if you decide to pursue this option. It's a good read just for employment and negotiation in general.