ran an update outside of transaction, can i roll it back in anyway ?

Hi,

This morning in a sleepy daze I typed

UPDATE boo SET foo = 6;

at the psql console. i meant to type

UPDATE boo SET foo = 6 WHERE x = 10;

I did not have this in a transaction, and have not vacuumed since
I pressed enter.

This is on PostgreSQL 7.2.4 on i386-unknown-freebsd4.7, compiled by GCC
2.95.3

Is there anyway that I can retrieve this data ?

[Please don't preach about backups, I've already
fwapped myself for that one]

Thanks folks,

Jeff.