Upgrading to SLI, will this work?

[qayin]

Hey!
right now my build is:
Mobo: Gigabyte GA-Z97X-SLI LGA1150, Intel Z97, DDR3 1600
GPU: ‏Asus GTX780 OC 3GB GDDR5 DX11 2xDVI HDMI DP PCI-E GTX780-DC2OC-3GD5‎
PSU: SeaSonic S12G-650 650W Gold Active PFC 12cm Fan PSU

Assuming i'd like to add an additional GPU, similar (maybe not ASUS) will this work?

i assume ill need a new PSU(do i have to?), will this one be ok?
http://www.seasonicusa.com/M12II-Bronze-650-750-850.htm (750w version)
i need it to be enough watts and have sufficient connectors.

And what about the mobo? where should i connect the additional GPU to?

thank you!@

 

[WildCard999]

-Yes you can use any other GTX 780 3gb, manufactor doesn't matter, only model and VRAM has to match.
-The 750W should work fine, its a Tier 2 PSU and is a quality model.
http://www.tomshardware.co.uk/forum/id-2547993/psu-tier-list.html
-Your going to want to plug in the second GPU into the 2nd PCI-E X16 slot (the other one with the clip that holds the GPU in). Don't forget to connect your SLI bridge that should of came with your MB.