Gz/tar are Linux files! You need to download the installer .exe file for Windows.
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Looking at it here (on Win10) it seems to be using 1.5GB RAM and 1.5GB VRAM... I reckon the 550 will run it but it will be a bit sluggish (30fps) and I wouldn't want you to be disappointed.
The 5xx series came out about 7 years ago I think - a lifetime ago for computer graphics. I don't think it'd cope with the things we're asking it to do at all (it would run, just ... rather slowly)