What are you advertising (I don't see any place to view your site)?
why don't you put link to your site?????
I visited your website and it looks like most of your members are women and/or moms.
I would display target specific ads. You will need to think about what these members would purchase or need. After you finalize that, seek out companies that could benefit from your type of traffic.
For example. moms by diapers, backpacks, school supplies, sports equipment and apparel, clothes, shoes, makeup, lingerie, small appliances, laptop computers, cell phones, and so on. I would make sure I was showing relevant ads to increase click through rates instead of relying on impression traffic.
With enough traffic and page views, you could almost charge anything you want for banner space.