FTTC - Router Replacement + Second AP

[#1]

Hi All
I have been a user of the Plusnet service for a number of years, and the router I originally received seems to be suffering when there is a high number of connected devices.  Therefore we are looking to get a replacement that can provide good 2.4/5G wireless signal, USB for file serving, and we would like it to be able to operate a second access point upstairs (I have Cat5e between the two locations).  Are there any recommendations from Plusnet users? At the moment I'm looking at ASUS but it seems to be very expensive, and I'm not ready to shell out for a Cisco Router and Wireless LAN Controller 
We have an FTTC service 35M/9M with the BT modem at present.
Kindest Regards
Jeremy.

[#2]

I've been happily running the Asus RT-N56U for 3 years, now only £65.00 from Amazon. It fits all of your requirements, is easy to set up & the latest firmware hasn't been changed for ages because it works extremely well.

[#3]

I'd second tijara33, although I have the slightly newer Asus RT-N66u, which is £85 on Amazon.  Been very happy with it

[#4]

Will that allow for a second access point to operate correctly?  In that both devices are managed and operate together.  I've had two routers (on different bands 1,11) installed before and had endless problems.  Some devices in the house drop out of wifi and start to eat expensive data plans.
Thanks for the responses!

[#5]

this may help:
http://www.thinkbroadband.com/hardware/reviews/76-asus-rt-n66u.html