Maybe a public apology -- "I was wrong", "I made a mistake", "I'm sorry", "I made incorrect assumptions about my company's support", "I will not make this mistake again, and this is why", maybe even "I wronged these two people".
Something like that owning up to her behavior, followed by a credible explanation that she changed as a result of the experience, and that her behavior was not to be interpreted as reflective of the company's values. Then followed by how she plans to make amends.
You're right about her mistake being public, so publicly trying to fix it seems an obvious option.