Remote control of a Mac that's behind a NAT
Without VPN-Functionality on the Router you have to rely on Software like 'LogMeIn' or 'Teamviewer' to access you Machine from outside your Home-Network.

As an alternative to LogmeIn you can use "Teamviewer". You have to install 'Teamviwer Host' on the Machines you want to control from outside and the regular 'Teamviwer' on your Machine.