[Build Help] Need some help.

Hi, a year or two ago I bought a PC without gaming in mind and now I was looking to upgrade. It's a Dell (I know, it was/is the only thing financially feasible, have credit there).

I was looking to get a decent graphics card This or This seem to be the best option available. The card has to be from Dell, again money problem.

That creates two problems. First my current power supply isn't enough to handle it so I was thinking of getting This.

The second problem is that my case is way too small. I currently have This case (the smaller one).

Height: 369 mm (14.52 inches)

Width: 110 mm (4.33 inches)

Depth: 437 mm (17.20 inches)

So I need suggestions on a case that would allow me to transfer my current stuff into it easily. Also if there is a better PSU please tell me. I would like to keep around the same cost. And please say if there are foreseeable problems with anything.

I have an i5 650 at 3.2 and 3x2gigs DDR3 ram. With the Graphics card I would like to be able to play most new games at around medium settings, does that look possible?

Thanks for the time and sorry if there are any mistakes, new to this sub reddit.