Sorry for your loss. I also noticed you have posted on the Phishing link. Thats about all you can do here within the Forums.
You could report the video to YouTube and they will take it down. Few hours later the guy will just put up another video. This is an on going issue with them that Jagex are trying to address.
I suggest you make a thread in Account Help section and you will be guided on how to secure the account as well as your system.
Sadly Jagex won't replace stolen items or wealth. You will need to make that back using some of your skills.
Please remember the fake pages are just that. They spam a user name for others to look up on YouTube. Don't fall for it. It's just a scam and no cash is ever given for leaving a comment on their fake page. You can report the spammer in game under WebSite advertising.