Instructions how to install the Huawei E173 Usb Modem Data Card 3G 7.2Mbps on Ubuntu 10.04/12.04 LTS
Download the driver from the following link to your download folder and extract it: https://ubuntu4u.com/downloads/linux.zip
Run Terminal and go to the download folder cd Downloads
Go into the extracted folder Linux cd Linux
Run the installation script sudo bash ./install
If you get the messages "The Linux NDIS driver is installed successfully." and "Finished, press any key to exit" everything went fine.
Reboot the system. Insert the data card and wait some seconds. After some seconds the connection software "Movistar 3.5G" will open. Press "Connect" and you will be connected (you don't have to bother that it says connect to "Movistar Banda Ancha Movil", it will connect to the Operator of the inserted SIM card).