Really enjoying it so far.
You can also get it from Amazon - https://www.amazon.com/BioShock-Columbia-Mehdi-El-Kanafi/dp/B078XX3MK7/ref=sr_1_1?s=books&ie=UTF8&qid=1521643638&sr=1-1&dpID=51vrtZURgXL&preST=_SY344_BO1,204,203,200_QL70_&dpSrc=srch
I suggest you to read this, its a great summary of the first bioshock which takes about an hour and 30 minutes to read (obviously has every spoiler of the game). It tells everything about the story and everything else you need to know for playing both BaSes. You don't have to know the story of bioshock 2 because it has nothing to do with BaSes.
I was probably too late, though.
The DLC should be mostly safe if you played all of 1. I found 2 to be a fun experience and its $5 on amazon. I still have my copy though Steam and I believe the Windows Live stuff is stripped out by the most recent patch.
*** more info here about not being able to buy digital copies