Which 650 ti to get?

Which 650 ti to get?
Hi, I've recently been looking for a new video card to put into computer. I did some research and decided the best choice for my computer would be the 650 ti due to it's size and power (if you think there's better choice for my computer, please comment!) I've narrowed my choices down to 3 brands. Which are:

PNY [dell.com]

GIGABYTE [amazon.com]

EVGA [amazon.com]

I'm more inclined to get the PNY, since I have a dell gift card, and also it has a life-time warranty, but the Gigabyte I hear has better cooling, and the EVGA I hear is very reliable.

My computer specs: Dell Inspiron 660
•PROCESSOR _ 3rd Generation Intel® Core™ i5-3330 processor (up to 3.20 GHz)
•MEMORY _ 8GB Dual Channel DDR3 1600MHz - 2 DIMMs
•HARD DRIVE _ 2TB Hard Drive, 3.5", 7200rpm, SATA
•VIDEO CARD _ Nvidia GeForce 1GB DDR3 GT620
•POWER _ 300W

Yes I realize I will need a new power supply also, and was wondering if 600+Watts will be good, even though the recommended is 400W.