There's a difference between release candidate and beta. A beta is like just testing, a release candidate is about to be released there are just some little things that need to be polished first.
I personally like the Xbox version better because of the improved graphics, it's not THAT noticable but I have every version possible of SA and Xbox is definitely the better choice than PS2 (depending on your preference of controller).
Sorry dude, but your computer blows. SA and any other modern game will run horribly on that PC. I suggest getting a new computer, all of your specs suck.
I can imagine it's harder making friends when your older, I mean, you don't really have school to meet up. I guess there is work but your all in competition sorta.