Will I bottleneck my PC with this GPU?

I have a Lenovo X700, and I would like to ask a few questions about it. I will also include upgrades that I have made, as I know they require more power consumption. As I'm not exactly familiar with estimating these values, as well as knowing how these newer parts fair when operating with my own; I thought it wise to ask the opinion of others. Being that my specs are rather different than that of Lenovo's site (as the machine advertised is much newer); I included my own below. All of my questions will be after the "specs list". Thank you.
Motherboard: I couldn't find a name on the board, when trying to observe it through my wire mess, though I could be missing it all together. I did find a site that sells replacements, but they too lack detailed "board specs", which I wished to know. Like, Do I have PCIe 2.0 or 3? Or, Is the second PCIe 16x a full 16?
CPU: Running CPU-Z, I was able to find that the system is equipped with a socket 2011 Sandy Bridge-E i7 3820, which is clocked at 3.60GHz. There's also a large stock water cooler that is installed.
Memory: 12GB DDR3 3x4GB, CPU-Z says the DRAM Frequency is 797.8, which I think means the speed of the memory is most likely 1600MHz. I would, if its possible, like to know what speeds I'm capable of, as well of how much memory.
GPU: Currently I'm still running the stock 1.5GB GTX 660 that came in the machine.
PSU: The system was equipped with a 610W power supply, that is included with 3 12v rails at 18A each. Detailed on the side of the PSU, a diagram seems to display that the 3 rails share a load of 475W. Since a lot of these 970s say something like "minimum 500W", if I'm correct I believe I'm short on power output. The EVGA card shown, is one of the pics requesting the min 500. If you can, if you could explain what actual "minimum" wattage the PSU must be, or is mine going to work?
Storage: 120GB SSD with boot OS, 1TB 3.5in for main storage, and I added two spare 500GB hdds that I had laying around. All three hard drives are hooked up internally, or via the front drive bay. I was desperate for space at the time of filling my 1TB, or otherwise I would have immediately purchased a larger drive instead of using the two other drives; either way though, it fixed my problem atm.
Optical Drives: Two separate drives, DVD-RW, BD-RW
The system will also run a few external peripherals such as a controller, Astro headset, 3 external HDDs and obviously the mouse and keyboard.
So, in conclusion… What I'm asking is whether or not my system will have difficulties/bottleneck with a GTX 970 or equivalent card. Also, if anyone can tell me a little more about my motherboard specs as well as how my system fairs in total, I'd very much appreciate it. As far as what card I was looking at purchasing, I thought the EVGA FTW 4G card was the best due to its higher "core clock" speed compared to its competitors (1216, compared to a lot of other cards which have 1056, or a bit higher). Either way, thanks to the Black Friday and the Christmas sales, most of these cards are sold out right now. Leaving either the cheaper cards, or the very expensive cards; even then, things are pretty "picked over" at the moment.
Thanks for your help guys, its not everyday that I spend 350-400$ on a new GPU; I wanted make sure its going to be correct on my behalf before I buy it.
BTW; Its not really relevant, but I just wanted to mention that I got the system in stock condition from CL for 500$; Did I get a good deal?
Thanks again guys…