The WR940n is a TP-Link...
Strangely, I had a spare TP-Link Archer D2 the other day, so I thought I'd see whether it was worth changing to that one as my 'extra' access point. Compared to the D-Link DIR-655 I'm currently using I did find it a little fiddly to set up. This may help:
http://www.tp-link.com/en/faq-417.html