So I was thinking about picking up The Hobbit to read before the final 3rd movie comes out. The books I've found have up to around 330 pages. Do these pages cover the entire story of the hobbit equivalent?? Meaning, does the single Hobbit book cover all three movies?? (3rd one not out yet).

The Hobbit book cover the first two movies and some of the third. But the third movie will mainly just be appendix material, at least that's my understanding.
http://screenrant.com/hobbit-3-peter-jackson/

Yes. Because, money. And because adding in all these extra sideplots annoy the readers (Myself excluded).

The general story of the Company of Thorin Oakshield (that is, finding the ring, Dragons etc) is all from the Hobbit. All the extra stuff (e.g. Most of the stuff about the Necromancer, 'Pale Orcs' etc) is added material thats either adapted from additional works based on Arda or made up entirely for the film.

Actually some of the added material is from hints in the book about the coming war of the ring, as in Lord of the Rings and these are signs of activity which leads Gandalf on his search for answers to these questions.

It's a good book but By the Nine it boring in some areas.

I don't know about boring but it is a merry fantasy story for children. Although, It's definitely a must read.

The book pretty much takes place entirely from Bilbo's perspective. It's about his adventures with the Dwarves and that's it. Everything else you see in the movie are events that happened "offscreen" in the book. Their occurrence was either implied to happen in the text, described more fully in supplemental materials, or were just made up for the film.

I'd just like to say that the dragon itself was phenomenal in this latest movie.