how to apply DSA-2157-1

[Edoardo Panfili <edoardo@aspix.it>]

good morning,

I am usiong postgres on squeeze.

Reading  DSA-2157-1 I can see that I must upgrade to 8.4.7-0squeeze1 but 
I can't find that package using http://www.debian.org/distrib/packages 
or apt.

This is my sources.list-------------------------------------------
deb http://ftp.it.debian.org/debian/ squeeze main contrib non-free
deb-src http://ftp.it.debian.org/debian/ squeeze main contrib non-free

deb http://security.debian.org/ squeeze/updates main contrib non-free
deb-src http://security.debian.org/ squeeze/updates main contrib non-free
------------------------------------------------------------------

What am I doing wrong?
Edoardo