can i get a higher GPU? is it a graphics card? http://www.newegg.com/Product/Product.aspx?Item=N82E168...
this one seems to have a better graphics card i think
but lower CPU? I'm not sure so I'm asking you.
and is there a difference between NVIDIA Geforce GTX 550Ti Graphic Card and Geforce GTX 550Ti Graphic Card
i'v seen both but i think they are the same
The 550 Ti isn't that great of a card. It's a solid low end card, but it's not going to be maxing out settings in modern games at 1080p. For that, you'll need to spend around $200 (or more, depending on the game) on the GPU alone.
I think these kits are a good starting point, but I think you'd get better results picking and choosing the components yourself, that way you know you get exactly what you want/need. $700 is certainly enough to build a budget gaming rig, but you're going to have to make some sacrifices.
If you're only interested in gaming, you can get a slower CPU because the GPU is by far the most important component in gaming. Saving $75 on a CPU means you can spend $75 more on the GPU and crank those settings up.