Could I upgrade the graphics card of this Computer?

Hello I was looking for a computer to buy with a decent processor and a good enough PSU so I can upgrade the graphics card to a Nvidia GTX 670 or 760. My budget for the PC is £400 and I will buy the graphics card later on.. I am currently looking at this PC but don't know if the power supply is good enough or the graphics cards I listed will fit in the case.

If anyone can help me out I will appreciate it. If you can find a better computer please link it to me.

Thank you for your help

No... just... no... they've got a 8320 on a microatx mobo, a coaster GPU, decent HDD, a WhoTF PSU, stock AMD cooler, which is also a coaster... 

basically... with that u're buying an 8320, HDD, and case...

That's what I'd do... of course the GPU is out of stock like it is in the states... consider other options if you need it RIGHT NOW but it's available for pre-order otherwise

That's a pretty bad setup.

Don't do it. Build something yourself.