Hi Guys I am a professional in this and hopefully this topic should be answered once and for all!
Firstly to answer some of your questions:
Why my DVR can only handle two simultaneous connection:
Its a basic DVR. doesn't have too much resources in the network section!
Does the DVR itself count as one of these 2 connections:
No
Now the main bit: All you need to do in order to watch the CCTV from home is to setup port forwarding properly.
Here is a free guide to help you in the process:
http://qrcctv.co.uk/cctv/cctv-port-forwarding
Please let me know if this helped!