Howto migrade form Debian i386 System to Debian amd64
1. get the manuell installed list of Debian packets on i386 system:
apt-mark showmanual > manual_debian_packets_list
2. install new amd64 system
3. cp manual_debian_packets_list to new amd64 system
install all automaticly
for i in $(cat manual_debian_packets_list); do aptitude -y install "$i"; done
will take some time 