Well I assume there are some smart hacker / security people in the NSA etc. who could be parachuted in to help if it really came to that.
I think these banks will probably be able to hire equivalent people in the private sector though and might not need the government help.
I work in infosec and work with many of these large organizations.
Simply put I don't think dropping in smart people in dysfunctional organization is going to have instant results. It will take a pretty long period of time to make them aware of all the systems with holes.
In the meantime hackers would be running off with actual information and money. More than likely I see banks turning off all kinds of systems in a panic and people with their money there being in an even bigger panic.