Как мне получить из другого зеркала?

Я нашел несколько сломанных репозиториев. Как мне поменять зеркало только для этого apt-get ?? Я использую Ubuntu Server 12.04.

    alex@****:~$ sudo apt-get install exfat-fuse exfat-utils
    [sudo] password for alex: 
    Reading package lists... Done
    Building dependency tree       
    Reading state information... Done
    The following NEW packages will be installed:
      exfat-fuse exfat-utils
    0 upgraded, 2 newly installed, 0 to remove and 2 not upgraded.
    Need to get 130 kB of archives.
    After this operation, 329 kB of additional disk space will be used.
    Err http://pl.archive.ubuntu.com/ubuntu/ precise-backports/universe exfat-fuse i386 1.0.1-1~ubuntu12.04.1
      Temporary failure resolving 'pl.archive.ubuntu.com'
    Err http://pl.archive.ubuntu.com/ubuntu/ precise-backports/universe exfat-utils i386 1.0.1-1~ubuntu12.04.1
      Temporary failure resolving 'pl.archive.ubuntu.com'
    Failed to fetch http://pl.archive.ubuntu.com/ubuntu/pool/universe/f/fuse-exfat/exfat-fuse_1.0.1-1~ubuntu12.04.1_i386.deb  Temporary failure resolving 'pl.archive.ubuntu.com'
    Failed to fetch http://pl.archive.ubuntu.com/ubuntu/pool/universe/e/exfat-utils/exfat-utils_1.0.1-1~ubuntu12.04.1_i386.deb  Temporary failure resolving 'pl.archive.ubuntu.com'
    E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?
    alex@****:~$ su
    Password: 
    root@****:/home/alex# sudo mount -t exfat /dev/sdb /mnt/extdisk/
    mount: unknown filesystem type 'exfat'