It is not a security risk if you are able to read your own WiFi key since whether you are running Windows or UNIX like operating systems, there are many ways, including through a GUI, to get it if you are connected to your hotspot at least once.
If you are worried about security then you can log to your router and change the default password that comes with it (and which every one can find on Internet), enable encryption on it (WPA2) and filter MAC addresses allowed to use your WiFi (since you are running Windows you can find yours by running
ipconfig /all so that you won't disable your own MAC address)
Also if you are using your WiFi only for yourself (I mean for you and the people living in your apartment) then you can decrease the signal range of your router by either using a different wireless channel or changing the mode of your router to 802.11g (instead of 802.11n or 802.11b). Last but not the least, disable SSID broadcasting and survey your connectivity logs.