My wired and wireless and datacard gets connected to the internet. But there will be no data transfer.. I have this problem when I upgraded from 12.04 to 12.10. I cant connect to internet to download broadcom drivers.. Help to get rid of this issue..
You can try to find packages you need at http://packages.ubuntu.com/, download them and install manualy. Otherwise you can mark all packages you need in Synaptic and generate download script, run script on other machine to download packages, copy it to you machineand install it (https://help.ubuntu.com/community/Synaptic/PackageDownloadScript).
You might try restart the connection by using ifup & ifdown. See if that work.
Also, are you using a laptop? If yes, for wireless, you may want to try "iwconfig eth1 power off" (whereby "eth1" is your wireless connection). Most of the time this issue happened only when run on battery, but sometimes it would happen on AC supply.
I would advice you to provide more info on your hardware configuration so it is easier to identify your problem.
My 2 cents.