Dear there
I believe your website is doable. About payment system, we may need to implement paypal recurring system, that allow your user could pay by monthly, or yearly basic... We need to have one time payment as well.
I have a lot of experience with this kind of work. Please discuss more with me, so I could know more about your old site freelegaladvice, so we could start now. I believe we need to rebuild most of thing...
Thanks & B/R