Wife got scammed by computer pop up ad to call tech support

So I was napping today and my wife got a pop up ad that her computer had a virus and to call 888-400-1925. The computer was frozen, so rather than waking me up, she called them, paid $349 and gave them access to her computer. I am certain they down loaded files from her computer which makes me really nervous. So what do I have to do? Maybe a system restore to a previous date? What else, as I don't want them hacking into our network or her computer again. Thanks

Wife got scammed by computer pop up ad to call tech support