TL-ANT2408CL is 2.4GHz antenna. Tplink doesn't have dual band antennas.

wireless adapter like TL-WN821 will not work. you cannot install driver on the printer and does your printer has the ability to connect wifi? I think not. what you need is a print server, so you...

What's the operating system? Try the public driver. Contact tplink for it if you cannot find one.

Your router will detect devices connected to the extender and show their MAC address, IP address and so on under wireless statistics or somewhere like that. Put those MAC addresses in the access...

If the light goes off and on, update firmware of the extender. Contact tplink support further troubleshoot.

May try firmware recovery if it's not covered by warranty any more.. http://forum.tp-link.com/showthread.php?81462-How-to-recovery-the-router-when-you-bricked-it&highlight=fitz