I had such a horrible time getting this card to work on my Aspire 4520, I will tell you how I got mine working after 2 weeks of trying. Before anything you need to blacklist ath5k.
YOU MUST BLACKLIST ATH5K OR THIS DEVICE WILL NOT WORK!
sudo gedit /etc/modprobe.d/blacklist
THEN ADD THE FOLLOWING LINE TO THE LIST:
After blacklisting the driver reboot the computer and continue installing the driver.
#1) You need to uninstall the madwifi that you installed from livna because it will not work.
sudo yum remove madwifi
#2) Download and unpack this snapshot from madwifi to your home directory:
#3) cd into the madwifi folder you unpacked into your home directory:
#4) cd into the scripts folder and run the following scripts and cd back into your home directory like so:
./find-madwifi-modules.sh $(uname -r)
#5) Compile the driver and install it:
#6) Here is where I had an issue every time when I would modprobe ath_pci it still wouldn't work, you can do this or skip it but I needed to run:
sudo /sbin/depmod -ae
#7) Then run:
sudo /sbin/modprobe ath_pci
Afte that you should be able to use Network Manager to connect.
Post any issues you may have while compiling, installing, etc.
I hope this helps!!
Here is the full install manual from madwifi