I left a company and one of my co workers found out how much I made, because it was left on the HR desk?

She has now blabbed to other coworkers and is mad that I made more than her. I don't work there anymore, but this is my personal business that I don't want to be public knowledge. What should I do? I still associate with a lot of these people including the one that snooped for the info. Also I think this is wrong that the HR manager left my info out in plain sight...