480W Power Supply enough for XFX ATi Radeon HD 5770? (Urgent)

Hello,

I am new to this forum, so I apologize if this is in the wrong category! I have been wanting to upgrade to an XFX ATi Radeon HD 5770 for awhile now. I'm getting bored of running Battlefield Bad Company 2 on low settings with my XFX ATi Radeon HD 4670. I wanted to know if my PSU is good enough for it. I saw that on tigerdirect.com, the memory speed is 4800 MHz, which seems a bit high to me. The recommended PSU is 450W, but I don't want to burn out my PSU because of stress and so on. Here are my computer specs:

Windows 7 Home Premium (64-Bit)
AMD Athlon II X4 620 @ 2.6GHz (not overclocked)
4GB DDR2 memory (2 sticks @ 2GB per stick)
XFX ATi Radeon HD 4670 (not overclocked)
480W Black Steel PSU

If this helps, these are the numbers on the 2 rows of my PSU:

Row 1: |+3.3V| |+5V| |+12V| |-12V| |+5Vsb| |Total|
Row 2: |28A| |34A| |18A| |0.8A| |2A| |480W|

This is the card I want to buy: http://www.tigerdirect.com/applications/SearchTools/ite...

I was hoping to buy the card this weekend, so any help would be great ASAP!  

Thanks -- gotsupra1337