I love when little kids who have never even made a simple html website get on the internet and proceed to tell me how to make tons of money. This seems to happen at least once a month. These are the same kids who suggest moving the site to freewebs or wherever to save money.
If I told you how much I actually spent on advertising, you would stuff your pants. stuff would come out of your ass. The majority of people who come to the site get there via clicking an ad. I am afraid it is reaching the saturation point on some venues. To get more out of it requires tweaking and targeting to individual demographics. It is not simple.