New PSU or not ?

[BMW_X6_50i]

Hey guys,

I'm planning on changing my GTX 560, to a GTX 760/770 or R9 280x/280/285, it will depend on what games are gonna be bundled with them, and how the prices will go down with GTX 900 and R9 300.

 

My rig:

i5 2320 @3GHz

GTX 560

8Gigs of DDR3 G.Skill Ripjaws X

Corsair Force GS 240gigs

1 tb HDD

A random samsung optical drive

MSI MS 7728 2.0 (this clearly says, "hey look at me i s*ck i'm from the market")

FSP450-60EMDN so 450W

 

According to Cooler Master's PSU calculator, with a GTX 760, i need minimum 405W, so this means that a GTX 760 is okay and won't make everything explode ?

When i try with a GTX 770 or a R9 280, it goes up to 470W, but it still recommends 450w PSU on the bottom, so i can or i can't use these ?

 

And also, it seems that i only have one 6 pins gpu connector, however the 760 have either two 6 pins connectors, or one 8 pins connector.

http://image.noelshack.com/fichiers/2014/37/1410717061-img-20140914-194340.jpg

http://image.noelshack.com/fichiers/2014/37/1410717060-img-20140914-194520.jpg

I have an option do add one ?

Thanks for your time.