If you're going to read the books, keep in mind the correct reading order:
1. The Last Wish
2. Sword of Destiny
3. Blood of Elves
4. Times of Contempt
5. Baptism of Fire
6. The Swallow's Tower
7. Lady of the Lake
Books 1,3,4 and 5 have official English translations which are available e.g. on Amazon both in paper and digital forms, while the other three books don't have official English translations yet (yes, it's completely weird that they skipped the second book). However, there are fan translations of these books available here:
http://forums.cdprojektred.com/threads/16494-Our-Community-Fan-Translations . They are of a very decent quality.
The first two books are collections of short stories, while the main saga starts from the third book and continues till the end.
On the topic of the games: The Witcher 1 & 2 are more self-contained than e.g. Mass Effect games, and everything indicates that it will also be the case with the third game. So you'll most probably be fine. By the way, The Witcher 1 doesn't require a very powerful PC. It's also available on Mac. I suggest you to try, it can actually run quite well even on a laptop. This game is totally worth trying.