Gaming pc help

I'm want to get a gaming pc instead of a new console this year. I had a gaming pc before that I bought off someone and it quit working the specs are 

Processor: AMD Phenom II X6 1090T black edition                                                               

Memory: Corsair 8gb DDR3 1333 MHz                                                           

Graphics Card: Zotac GeForce gts 450                                                                           

Power supply: Radimax 630w..... couldn't find a link to this one

Motherboard: gigabyte 870a                                                                                                         

so i have narrowed down what the problem is and i think it is the power supply or Graphics card so my real question is could i take out my graphics card and power supply and put in a 

HIS 7950 IceQ                                                     

and a new power supply

XFX 550W                                                         

with the new graphics card and new power supply would my motherboard and other stuff be compatible and still work right?  Also, would this be better than the new consoles?

Everything should work. If it was me I'd spend a bit more and get a 7970 and a 600w or better power supply, but these are perfectly fine choices.

if you are certain that it is either your power supply or graphics card, then it should work again after that. The powersupply has sufficient connectors and power to handle the card so that's no problem.

Though you will need to do a fresh install / run driversweeper to remove the nVidea drivers from your old graphicscard if you put in a 7950.