You need the admin name and admin password to login into the router and look if the current password is shown readable or you have to change it. So if you have that, you're nearly done.
Now find the gateway address (using the IPCONFIG command in the command prompt of a PC that has a wired connection) and enter that (something like 192.168.1.200) into the address bar of your router. You might need to put http:// in front of it.
But, just as well, it's possible that the SECURITY or (more likely) the PASS PHRASE you wrote done is the password that you should type in now on that new laptop. I would try that first.
For a router from 2009 there's a 99% chance the manual can be downloaded from the manufacturers site as a pdf file. Did you try that?