did a google search on that image of the hand came up with a tutorial but.. Its very interesting to see his name "neimadthehacker"
Can't read this language at all
Click Here
Click Here
Looked at all these sites that have been hacked by them
Google Search Results
Not sure if any of this helps but I am pretty good at tracking down the source of hackers I have had my fair share. Also best way to get your site back online is what you are doing now do a restore because hackers usually put "Rogue" files that are very well hidden and will carry key loggs among other things.
Sorry this happened to ya best thing to do is contact your host tell them what happened and ask them to help ya secure your site/webserver and they will help you because if someone trys to do a ddos attack on you that can cause multi millons in damage depending on how big it is and they won't want that trust me.