I unpluged my remote camera monitoring sys...

The IP address on your camera system is probably setup using DHCP. This means that the IP address it's given will change over time. There's an easy way to find it. Log into your router, and locate an option called "DHCP Clients Table". This will list every system on your network, and one of them has to be the camera system.
If your router does not have a HDCP clients table, then you'll have to either do a network scan using something like bluesportscanner, or nmap, or to log directly into the camera system using a serial cable or something similar.
Comment back with your specific camera system model number, and I can provide more assistance.
Steven