What do you hope to gain by installing a discrete graphics card?
The n3700 processor is abysmally weak.
I have one in a laptop.
If you hope to play games a GT1030 low profile card is a 30w card and may do ok with the 65w psu.
Before you buy, try this test:
Run YOUR games, but lower your resolution and eye candy.
This makes the graphics card loaf a bit.
If your FPS increases, it indicates that your cpu is strong enough to drive a better graphics configuration.
If your FPS stays the same, you are likely more cpu limited.