Can I upgrade my ASUS Essentio Desktop M51AC Graphics Card/PSU?

[FishSauce]

Hello, I am really new to upgrading pc's even though I have been looking into it for a while. I have an ASUS Essentio Desktop and I am looking to upgrade the Graphics Card and PSU. I haven't opened up the case yet so im not sure if I have a good enough PSU but I am going to assume that it isn't good enough. This is probably a really, really stupid question, but I don't see more than one port for a graphics card on the back of my PC. Can I get a GTX 970?

 

[cin19]

You can, but just make sure that you need open the case to make the measurement for the gtx970, like http://cdn.overclock.net/e/ee/500x1000px-LL-ee575342_P1010034.jpeg also you can find the gtx970 dimensions from the manufacturer website.