Can I install extra drivers via the command prompt?

For 14.04 and above

sudo ubuntu-drivers list

Will show all the driver packages which apply to your current system. You can then

sudo ubuntu-drivers autoinstall 

to install all the packages you need, or you can do:

sudo ubuntu-drivers devices

to show you which devices need drivers, and their corresponding package names.

For 12.04 and below

The additional drivers program has a command line interface, jockey-text:

Use

jockey-text --list

to get a list of available drivers and their status, then use

# the init lines are required only for graphics drivers
sudo init 1
jockey-text --enable=DRIVER
sudo init 2

where DRIVER is the one you got from the list. For example:

jockey-text --enable=firmware:b43

To install the Broadcom B43 wireless driver.

For your graphics card, you will get a choice of the proprietary driver from the manufacturer and a free alternative. You have to either restart the display server (log out and back in) or restart the system entirely (recommended).

For 12.04 and below

The internal name of the "additional drivers" program is jockey-gtk. There's a console version with the same functionality called jockey-text in the eponymous package. It should be installed by default.

You should be able to use

jockey-text -l

to list the available drivers and something like

jockey-text -e xorg:nvidia-185

to install one of the options listed. You should select the most appropriate driver listed.