Hi
The first step would be to unplug the network from the computer, as technically speaking someone else now control your computer remotly.
If you are certain it was hacked, I would ask someone to plug your hard drive inside another computer to be able to copy your data if you dont have a backup near.
I would replug the hard disk, format, reinstall and after restore the needed files, that possibly you was able to scan for virus on them before restoring.