Looking a repository for your ubuntu 11.10? don't worry, i have some repositories for your region you live. Here it is.

Kambing UI's repository.
+ --------------------------------------------------------------------------------------------------------------------- +
deb http://kambing.ui.ac.id/ubuntu/ oneiric main restricted universe multiverse
deb http://kambing.ui.ac.id/ubuntu/ oneiric-updates main restricted universe multiverse
deb http://kambing.ui.ac.id/ubuntu/ oneiric-security main restricted universe multiverse
deb http://kambing.ui.ac.id/ubuntu/ oneiric-backports main restricted universe multiverse
deb http://kambing.ui.ac.id/ubuntu/ oneiric-proposed main restricted universe multiverse
+ --------------------------------------------------------------------------------------------------------------------- +

ITB's repository.
+ --------------------------------------------------------------------------------------------------------------------- +
deb ftp://ftp.itb.ac.id/pub/ubuntu oneiric main restricted universe multiverse
deb ftp://ftp.itb.ac.id/pub/ubuntu oneiric-updates main restricted universe multiverse
deb ftp://ftp.itb.ac.id/pub/ubuntu oneiric-security main restricted universe multiverse
deb ftp://ftp.itb.ac.id/pub/ubuntu oneiric-backports main restricted universe multiverse
deb ftp://ftp.itb.ac.id/pub/ubuntu oneiric-proposed main restricted universe multiverse
+ --------------------------------------------------------------------------------------------------------------------- +

UGM's repository.
+ --------------------------------------------------------------------------------------------------------------------- +
deb http://repo.ugm.ac.id/ubuntu oneiric main restricted universe multiverse
deb http://repo.ugm.ac.id/ubuntu oneiric-updates main restricted universe multiverse
deb http://repo.ugm.ac.id/ubuntu oneiric-security main restricted universe multiverse
deb http://repo.ugm.ac.id/ubuntu oneiric-backports main restricted universe multiverse
deb http://repo.ugm.ac.id/ubuntu oneiric-proposed main restricted universe multiverse
+ --------------------------------------------------------------------------------------------------------------------- +


ITS's repository.
+ --------------------------------------------------------------------------------------------------------------------- +
deb http://mirror.its.ac.id/ubuntu oneiric main restricted universe multiverse
deb http://mirror.its.ac.id/ubuntu oneiric-updates main restricted universe multiverse
deb http://mirror.its.ac.id/ubuntu oneiric-security main restricted universe multiverse
deb http://mirror.its.ac.id/ubuntu oneiric-backports main restricted universe multiverse
deb http://mirror.its.ac.id/ubuntu oneiric-proposed main restricted universe multiverse
+ --------------------------------------------------------------------------------------------------------------------- +

===================================================================================
I know you can make setting it.
If you can't set it up, open terminal and write this:

1. sudo -i ("input your password")
2. nano /etc/apt/source.list
    Clear all text. Choose one repository (copy one of several repositories then paste on it), and push "ctrl + x" then save "y"
3. apt-get update
===================================================================================

Good Luck!