We can certainly help you with the skin tones, eyes, etc, but any of the anatomically correct stuff you will have to go to an adult site to get.

First of all, there are a lot of custom skin and eye replacements for Sims 3 on a few sites. I would suggest going to Mod The Sims as a starting point. Club Crimsyn has a default skin/eye replacement and Garden of Shadows does too. (You can find all these sites on Google)
The Sims 3 already has sliders available in CAS that allow you to customize fat/thin/muscular body types, but if your looking for more, Delphy at MTS made a slider hack that allows users to get further customization with body/face shapes, as well as a hack that will allow you to further modify breast size on women. There is a caveat though. If you have WA, neither are compatible. If you don't, you should be OK, but the slider hack isn't compatible with the most recent patch. I don't use either, so I'm not sure up to watch patch it's compatible with.