Now, I'm wondering if it's worth buying Windows 7 x64 and new RAM for this questionable game.

Have you been living in Russia for only one day?
And if we're talking about the game, it's definitely worth it, and those extra 4 GB of RAM are a must. :D I work with computers, and of course, most people have 4 GB, but those who play decent games have 8 GB or more. Personally, I'm still good with 8 GB for everything.
This game is definitely worth buying, 100%. But I've already figured it out on Steam... We'll see. =))
Of course, I was looking at the standard edition... The Deluxe edition is already too expensive.