CC, if you buy a custom built machine you will get a warranty with it - normally 2 years (although some places give you more, some less).
This is your graphics card (GT 620) on the graphics card comparison chart :
http://www.videocardbenchmark.net/video_lookup.php?gpu=GeForce+GT+620&id=1429
And this is the graphics card from the SSE minimum requirements :
http://www.videocardbenchmark.net/video_lookup.php?gpu=GeForce+8800+GT&id=1279
3D work (especially texturing and rendering) will become difficult if your models start to become complex.
So, long story short, your "new" graphics card is below the minimum requirements for SSE, and you'll struggle to use it for any major 3D work.