" It is secured but if I leave it on permanently, can other people access it. "
No. Unless they have the code.
" I do not seem to need to put in the security key every time. "
You only need to enter the code in once on each computer. the computer is then paired with the router and will connect automatically.
The security side of things look fine.
As to linking your laptop, do you want it to be wired to the router? If you do, turn off the WiFi signal and disable the WiFi network in control panel.