I use online banking, and have done for the last 20 years (well, back then it was just leased line and direct connection), but I never use public WiFi - flowrider99, that's the most likely way they got in: plenty of script kiddies using ready-made packages in Starbucks and suchlike (unless it was an inside job). My own network is reasonably secure, and I do not use an operating system that requires an anti-virus software ...