File server configuration

Hi We have a server (microsoft server 2008 R2) on a little bussines, there are 4 users and they need to access common data fro inside and outside the enterprise, we have 2 windows 7 machines and 2 MAC machines. The VPN tunnel is created on the firewall and is working, we can access the server from the windows machines, but not from MAC machines. We need 3 things: 1-Control the use of the common files, I mean if someone is using a file and other user tries to access the same file the system must advice that user that the file is in use. I dont know if this is this an option on windows server 2008r2 or we need an extra software. 2-Maintain a version control of those common files. I dont know if this is this an option on windows server 2008r2 or we need an extra software. 3-Get the VPN access from MAC machines working. If some know how to do it all, perfect if not we can divide the project in 2 different parts. Part 1: Points 1 and 2 Part 2: Point 3 Thats all Thanks in advance