Upgrade GTX1060 on Alienware 17 bought 2014? Default: M290X

Hi All,
I bought this Alienware 17 in 2014, default configuration as below:
CPU: i7-4710MQ 2.5GHz
Graphic: Radeon R9 M290X
RAM: 8 GB DDR3 1600MHz * 2
Power: 240W (saw it in BIOS)
System: Win8.1

I saw @loafer987 upgraded his Alienware 17 R1 with a stunning 1070 graphic.
I'm wondering can I upgrade mine to GTX1060 without extra power supply?
My target is to run Dark Souls 3 and The Witcher 3.

Many thanks.

Upgrade GTX1060 on Alienware 17 bought 2014? Default: M290X