Ask HN:How to find where your target users hangout online?

Hrm. Your target demographic is super wide! I don't think there's a tool that does this. But you can possibly do it this way.

Run a Facebook Ad campaign for 3 days (at $10 a day max budget), Then interview all those that "liked" your page or signed up for your form personally. To build their user profiles.

Nice advice. I will give it a try.

Umm, shouldn't you be focusing on something like revenue per click/CPC? Also, a less-broad demographic may work better...

Quantcast usually contain some information on demographics.