How to Install Atheros Wireless Drivers for Elementary OS ?

Please try:

sudo apt-get install  linux-backports-modules-cw-3.8-precise-generic

I believe cw-3.8 includes the modalias for your device.
If your device is still not shown, please post:

modinfo ath9k | grep 0036
dmesg | grep ath

Please get a working ethernet connection, open a terminal and do:

sudo apt-get install linux-headers-generic build-essential

Download this file to your desktop: https://www.kernel.org/pub/linux/kernel/projects/backports/2013/11/13/backports-20131113.tar.bz2 Right-click it and select 'Extract Here.' Back to the terminal:

cd Desktop/backports-20131113/
make defconfig-ath9k
make
sudo make install

Reboot and let us know if it is working. You will have compiled the driver for your currently running kernel only. When Update Manager installs a newer kernel version, also known as linux-image, after you reboot, re-compile:

cd Desktop/backports-20131113/
make clean
make defconfig-ath9k
make
sudo make install
sudo modprobe ath9k

Please retain the files and these instructions for that time.

Thanks to Chilli for this info.