Debian6 still only ships GCC 4.4, so no joy playing with C11 & C++11 yet. Wheezy does have 4.7 GCC packages but it's generally not a good idea (nor for the faint of heart) to mix and match apt-get packages between major Debian releases (at least I chicken out on that).
Next option is to build and install GCC from source:
If this is a minimal or new/clean install, make sure you have enough dev tools on-board:
sudo apt-get install build-essential manpages-dev autoconf2.64 automake1.9 autogen m4 git git-doc zip unzip
wget http://bugseng.com/products/ppl/download/ftp/releases/1.0/ppl-1.0.tar.bz2 wget http://www.bastoul.net/cloog/pages/download/count.php3?url=./cloog-0.17.0.tar.gz wget http://www.multiprecision.org/mpc/download/mpc-1.0.1.tar.gz wget ftp://ftp.gmplib.org/pub/gmp-5.0.5/gmp-5.0.5.tar.bz2 wget http://www.mpfr.org/mpfr-current/mpfr-3.1.1.tar.bz2 wget http://www.netgull.com/gcc/releases/gcc-4.7.2/gcc-4.7.2.tar.bz2
see also GCC prerequisites.
for file in *.tar.gz; do tar xzvf $file; done for file in *.tar.bz2; do tar xjvf $file; done
You should now find the 6 source directories, ready to build.
Don't install into /usr or /usr/local; instead create a .deb package and install via package managment