You have to install alternative firmware on WR841, then you will see client mode (Gargoyle or DD-WRT). http://wiki.openwrt.org/doc/howto/clientmode http://www.dd-wrt.com/wiki/index.php/Client_Bridge

You have to connect TP-Link by WAN port.

Can you give me some informations about ISP and as you have the internet connected to the router? Can you show me screen shot from TP-Link status tab?

Can you try 30/30/30 hard reset - http://www.jimasek.elektroda.eu/index.php/poradniki/66-hard-reset-30-30-30

TD-W8961ND_V2_120710_UK This is the latest firmware for your hardware version.

http://www.tp-link.us/faq-395.html