Passphrase and/or locked wallet ONLY affects the wallet.dat file... if the hacker had your private key, then all the passphrases in the world won't save you. Did you ever export the private key for the address: 1Q1PDnwmbFkNaYbpsiPVUBJe1pEM7m8zYH? 
As annmarie suggested, that entire wallet should be considered compromised and you should no longer receive ANY coins to it. I recommended moving any coins you have left to a new wallet immediately. I see that 1Q1PDnwmbFkNaYbpsiPVUBJe1pEM7m8zYH just received more coins today. You need to STOP using that address immediately and move those coins as soon as possible.
You should probably also scan your computer for viruses/malware.
As annmarie suggested, that entire wallet should be considered compromised and you should no longer receive ANY coins to it. I recommended moving any coins you have left to a new wallet immediately. I see that 1Q1PDnwmbFkNaYbpsiPVUBJe1pEM7m8zYH just received more coins today. You need to STOP using that address immediately and move those coins as soon as possible.
You should probably also scan your computer for viruses/malware.