Pro Sites help...Need to limit sites members from creating more sites then one

Hello,
I need to limit members from creating more then one site. (first screenshot)

I also need to be able to restrict their permissions automatically when they join so they don't have access to certain parts of their site i don't want them to have access to. The arrows represent what i don't want my members to see when they make a site. (second screenshot)

2nd screenshot: