Here's the solution:

1) Use a LAN cable to connect your computer to your router or use a friend's PC who could access your wireless network.
2) Log in to your D-Link control panel via 192.168.0.1 in your browser. Enter username as "admin", password leave blank. Click on Login button.
3) Go to Wireless Setup on your left hand panel.
4) Go to Manual Wireless Connection Options section, click on the Manual Wireless Connection Setup button.
5) Go to Wireless Network Global Settings, un-check the Enable Auto Channel Selection option.
6) Change the Wireless Channel to 11.
7) Save the settings. Restart your computer, and then magically, you could reuse your wireless unifi connection again!