way to have a user sign-up/login page before "home"

I am using a simple WP site for plant managers to order items to be shipped to them. there is no money exchange - it is a way to simplify orders and get them to the correct manager.

I am using the following:
WordPress 3.5.2
MarketPress eCommerce 2.8.7
SimpleMarket Theme 1.1.1.5

I want to have managers create an account.
Only people logged in can see site.
Admin needs to approve new accounts.

Is there a plugin that does the above?

TIA,
Greg (for Carl)