Adding laptop to my wireless

You can't if you don't know the password. Did it come with your internet contract? My ISP gave me a card with my wireless password on. My old router had it wrote on the bottom of it as well.
 


You have to log into your wiress router (assuming it's the same device) and somewhere under the Wireless settings will be Security. There you will see the options. If you have Zero devices connected wireless now, it's easiest to just change the password to whatever you want.

Connect an ethernet cable between the laptop and the wireless router. Run CMD.exe and type in "ipconfig /all", then make a note of the Ethernet Adapter Local Area Connection - Default Gateway ip address. That IP is the address you need to type into your internet browser to log into the wireless router.