Connecting a wireless nanny cam to iMac - no RCA connection

I have just migrated from the PC to Mac world. I have a wireless nanny cam that I use to record to my PC (like a DVR) by installing in my PC a DVR/PCI card that has RCA input jacks. A receiver would connect into the RCA jacks and thus receive the wireless camera signal. I now use an iMac

Obviously I can't install a PCI card on my iMac and it doesn't have RCA inputs either, so how would I receive a signal on my iMac from a wireless camera? It is not a camera that has its own IP address. I thought that since the latest iMacs are able to pick up wireless router signals for internet connectivity, that it could also be configured for a wireless camera that transmits a signal. Do I have any hope? FYI, the software used to manage the camera recordings is called Pico 2000.