System security check - Wifi Users to be blocked in my PC Wifi Network

Hi I have to check my System's (PC) WIFI network security, so as to whether any external wifi (anonymous network) is connected to my WIFI Network, to check my PC Network Security Using "Wireless Network Watcher" Software, that is identifying the External IP Addresses, connected to my Network I want to get them blocked. I havee a reference Video (Youtube) regarding What to Do. I need the guidance for the same. My budget is limited to 500/- INR, as it is one time task and ofcourse smaller. Thanks