VPN setup for Cisco router

I have a small mortgage company. I need to set up a VPN with my existing Cisco 1801 router. I need to set up an IP address where my employees can log into with a unique user name and password. Once an employee puts in their unique username and password, a remote server desktop will appear. It is important that I can easily place only the items that I wish to appear on the employees desktop. Also, no employee should have any permission to work on any server files but their own. Each employee will also have a unique folder located on their individual remote desktops where they can place .pdf files to save on the server.