How can I connect my DVR to the internet using a shared IP

I use a shared IP address my DVR name is Real Time 16CH, I connect the DVR to my router wish I use port forwarding and the software that came with it is call Net viewer16ch and on my DVR network setting I only have:
DVR setting:
IP: 192.168.1.13
Subnet: 255.255.255.192
Gateway: 192.168.1.1
Http: 80
AV port: 5000
Command port: 5001

If am using my internet where my DVR is connected to, I connect and view my camera but if am at home I find it difficult to connect what can I do.