Recommend a Wireless-AC router

Hi guys I am in need of an upgrade on the home networking side of things.

I am currently running an Asus RT-N16 and I am getting a lot of interference issues on the 2.4ghz band. Also my range isn't that good, I get maybe 2-3 bars from where my computer is (upstairs), and I can't exactly move my router (living room). It has to stay at the far end of the house.

I am thinking of upgrading to Wireless-AC so I need some recommendations.

-between $100-$150 CAD
-Must have custom firmware available (DD-WRT or Tomato)
-Needs good range, (~15m, )
-Canadian vendor (ncix, cc, amazon, etc) (preferably shipping :))
-Ability to flash MEGA custom firmware version
-lots of RAM

I was looking at Asus RT-AC56U but I found from reviews that the performance and range isn't that good, so I might return it when it arrives so I don't get hit with a restocking fee.

Get the highest end Asus router you can. I had an N56U and it served me well. Upgraded to AC3200 recently and both have been excellent. Perhaps try to get the AC2400 or wait for the new models to come out later this year.