Connect your range extender with pc or laptop via ethernet and configure it with your wireless name and password.
Now put your range extender at that place where you are getting weak signal,it catch weak signal and through it further.
"When you are connected to your Range Extender, you can access the Range Extender’s Web-Based Advanced User Interface (UI) using your Internet browser. In your browser, type “belkin.range.” Then press the “Enter” key. This page shows the detailed status of your Range Extender."