I'm not an insolvency specialist, but if the company is still trading, even with new owners, it is still liable for its debts. There's usually a contract between the previous and current owners to agree who ultimately bears the cost of any liabilities, but that's nothing to do with the company's creditors. So unless the company has been placed in liquidation and she has taken over the business but not the actual company, you should still be able to go after them.
And if it is in liquidation you can put a claim in to the liquidators, but I wouldn't hold out much hope of getting anything back. The preferential creditors like HMRC usually get most of the cash unfortunately.