Compatible graphics card, Alienware x51

[Julia_97]

Hi! I have an Alienware x51, with an Intel graphics card. I want to upgrade my graphics card because I am not able to play many of the games I've bought, but do not know which one to choose. I have read that there are not many graphics cards out there that are compatible with the x51. I am NOT good with computers, and would appreciate some guidance. So my question is: which graphics card should I get for my Alienware x51?

 

[Julia_97]

PCPartPicker part list / Price breakdown by merchant

Video Card: XFX Radeon R9 270 2GB Core Edition Video Card ($109.99 @ NCIX US)
Total: $109.99
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2014-11-29 11:41 EST-0500

Small space in there! This seems to be the only one that'll fit.

Thank you for the response! However, I just wanted to ask to be sure: will my power supply hold? And are those graphics card cables compatible as well (the ones with 6 pins, 8 pins etc.) both in size and number? Julia