Technically speaking, there really is no better demographic. SFI is for everybody and anybody over the age of 18 who wants to take control of their financial freedom.
So if you want to advertise to retirees, you can do that.
If you want to advertise to homemakers, you can do that too.
My best answer for you would be to post ads targeting both demographics. This way, you'll have a chance of getting PSAs from both sides of the fence.