Whats the difference between the beta and the full game?
EDIT: I've not got a gaming PC just a Notebook Laptop to play it on.
If you buy beta, you get all updates leading up to the full game, plus the full game, for free.
Basically they're still just adding stuff and bugfixing. Single player is already stable for the most part, though.
I'd wait a bit longer to make sure your laptop can run the game, but if it can, and that's the only thing holding you back, I say don't hesitate, just buy it. It's not even a finished product and it's easily one of my top 5 favorite games of all time.