The number of "double spends" (most of which I believe is mutated transactions) for the last 24 hours:
2014-02-11 16960
(will edit OP to reflect this)
It is slightly lower than I anticipated, as it was already above 16k 9 hours before the CET day ended (24 hours). Maybe the attack subsided, or someone is having a break.
this is probably related to the current malleability attack on the bitcoin network (25% of transactions were affected today). it has nothing to do with your theft.
In addition to the above jgarzik is quoted on reddit to have said that one home PC could have done this. One home PC can screw up 25% of transactions!
Hold on. Are there actually any reports of something being screwed, apart from couple of exchanges who stopped withdrawals as a precaution measure?