Hi, it's not bad. I have an SMS jokes blog... and the ppc is around that margin for me aswell. My advice is don't write the content according to the keywords...you are doing well..just do the same..but if you can increase the traffic 2-3 times more, then it'll be excellent. Good luck.
You have at least earned more than what I earn, that is, $0.03 per click. I suggest you increase your traffic to increase the clicks which is increase your earnings.