Most routers can be accessed from inside your network at 192.168.0.1 or 192.168.0.10 or 192.168.1.0
Look at your dynamically assigned ip to figure out the start range.
Most will default to a login of admin with no password.
If it asks for a PW you can always reset to factory defaults by inserting a paperclip into the reset in the back. I WOULD NOT ADVISE DOING THAT RIGHT AWAY.
Some ISPs configure specific connectivity info, (DSL) that can get blown away.
Here's a link to the manual in case you don't have it.
http://www.myacrobatpdf.com/8429/dlink-wireless-router-dl-524-setup-instructions.html#