Upgrade from 12.10 to 13.04 fails and APT doesn't work properly

When trying to upgrade my release from 12.10 to 13.04 I get this output in terminal:

axept@aXept-Lifebook:~$ sudo do-release-upgrade

Ser etter ny utgave av Ubuntu
Traceback (most recent call last):
  File "/usr/bin/do-release-upgrade", line 144, in 
    fetcher = get_fetcher(options.frontend, m.new_dist, options.data_dir)
  File "/usr/bin/do-release-upgrade", line 37, in get_fetcher
    from DistUpgrade.DistUpgradeFetcherCore import DistUpgradeFetcherCore
  File "/usr/lib/python3/dist-packages/DistUpgrade/DistUpgradeFetcherCore.py",       line  30, in 
   import tempfile
EOFError: EOF read where not expected
Error in sys.excepthook:

Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/apport_python_hook.py", line 64, in              apport_excepthook
from apport.fileutils import likely_packaged, get_recent_crashes
File "/usr/lib/python3/dist-packages/apport/__init__.py", line 4, in 
from apport.report import Report
File "/usr/lib/python3/dist-packages/apport/report.py", line 12, in 
import subprocess, tempfile, os.path, re, pwd, grp, os
EOFError: EOF read where not expected

Original exception was:

Traceback (most recent call last):
 File "/usr/bin/do-release-upgrade", line 144, in 
 fetcher = get_fetcher(options.frontend, m.new_dist, options.data_dir)
 File "/usr/bin/do-release-upgrade", line 37, in get_fetcher
 from DistUpgrade.DistUpgradeFetcherCore import DistUpgradeFetcherCore
 File "/usr/lib/python3/dist-packages/DistUpgrade/DistUpgradeFetcherCore.py", line      30, in 
 import tempfile
EOFError: EOF read where not expected
axept@aXept-Lifebook:~$

And when running apt-cache info:

axept@aXept-Lifebook:~$ apt-cache policy ubuntu-release-upgrader-core
ubuntu-release-upgrader-core:
Installert: 1:0.190.7
Kandidat:   1:0.190.7
Versjonstabell:
*** 1:0.190.7 0
    500 http://no.archive.ubuntu.com/ubuntu/ quantal-updates/main amd64 Packages

    500 http://gb.archive.ubuntu.com/ubuntu/ quantal-updates/main amd64 Packages
    500 http://security.ubuntu.com/ubuntu/ quantal-security/main amd64 Packages
    100 /var/lib/dpkg/status
 1:0.190.1 0
    500 http://no.archive.ubuntu.com/ubuntu/ quantal/main amd64 Packages

And:

sudo apt-get update && sudo apt-get upgrade

Don't do anything. All is up to date apparently..

Trying to launch "Update Manager" gives the same error as "do-release-upgrade".
Tried to remove .pyc files in /etc/apt/dist-packages/ and reinstalled python stuff as found in a Bug-report...

Any suggestion?

This install is NOT new, my laptop has been running fine for months without problems.

Btw, running "Software packages" from "system-settings" doesn't work. It won't start. Suppose its the same reason.. Its been slow to start before, but now it just won't start.

UPDATE: Get the same error when trying to add a repository from terminal.. Whats going on??????

UPDATE 2: When "Update Manager" launch automatic with new system updates, it doesn't work. Nothing happens when I click "Install now" button..

This is not a running problem anymore.

Re-installed a fresh install of 13.04. Didn't find any other solution.