Hi guys,
I used bitcoin-qt as my bitcoin wallet and I forgot to setup a password

So today I checked my wallet and a very small amount of bitcoins were stolen:
https://blockchain.info/de/address/1CPEdjFu6TaZpPFGQ81zHaW7prtJ1pk8LVIs there any chance I get these BTC back? Or do I have to pay to learn the lesson?
After that, I moved to multibit and saved it on several USB-Sticks with a strong password using KeyPass obfuscating. Is there anything else I have to take care of?
Thx for your help!
Regards
My suggestion is to not use Microsoft Windows and to use GNU/Linux instead, and yes encrypt your wallet. If one originally created the wallet on Microsoft Windows move the coins to a new wallet created on GNU/Linux. I have been involved with Bitcoin since 2011 and have not lost a single satoshi to malware; however I would not let a single of my satoshi near Microsoft Windows. Make sure to make multiple redundant backups of wallet.dat and keep in mind that after 100 transactions the change or received funds are no longer backed up when using Bitcoin-qt. A good habit is to back up wallet.dat after 20 transactions or so.
By the way I stopped using Microsoft Windows for fiat banking back in 2006 before Bitcoin even existed for the same reasons.