Firstly don't be using any of your important apps, especially banking. In most cases samsung will be able to plug in and find and destroy the malicious hacking app.
However, it's what you do up until then that can get you into trouble. Think about emails, personal information. Most important you should not be connected to the internet as that would be the gate to transfer information.
If all else fails and you desperate, a factory reset will get rid of everything malicious.
Tough but worth it, I'm sure I don't need to remind you that you should let your bank know of this and stop payments of any kind until you are happy that the issue is resolved, than change all your passwords for good measure.
