I have read all of the WD comics to date. I started with the graphic novel collections like you have Nick, then switched over to monthly books around issue #85-90 I think. Finally caught up and got tired of waiting 6 months for the next part of the story. If you really like the show, you should read the comic. The stories are so divergent now that it's like reading an alternate universe storyline or EU or maybe even an initial script for the show. Yes, some parts of the story will overlap, but I don't think it would spoil anything for the show, since you never know where they're going to take things. There are already so many differences between the two in the current storyline:
TV Andrea is dead, but continues to be a pivotal character in the books
Daryl and Beth and Sasha are all non-factors in the book versus the show
Shane lasted longer in the show, but Rick's wife died much sooner.
Judith's story is very different, as was Sophia's
Carol is a totally different character in the book and was never banished from the group
There was no flu/plague in the book
It really is like a reading a vastly different story where some of the characters have similarities and some are totally different. If you like Alternate Scenes, Expanded Universe, Marvel What If, etc. then you will like reading the book. Besides, book Abraham totally rocks.