How can I get my wifi to work on my Dell 3521 laptop?

How can I get my wifi to work on my Dell 3521 laptop?

I have installed ubuntu 12.04 alongside windows 8 in my DELL 3521 laptop
and everything is working fine except the wi-fi in ubuntu. In win 8 wifi
is working well but when i start ubuntu it does not show any wifi options.
i have tried installing all the drivers required but still not working. I
dont know its because of the wi-fi car (Atheros) or something else. can
someone please tell me the solution for this problem. additional
information about the card-
Atheros Communication Inc. Device [168c:0036] (rev 01)
subsystem: dell device [1028:020c]
Thanks in advance.