I can't say yes or no.
I agree with both sides here so far.
The $500 could be used for a bigger push - KND, Pixel, plus some freebie copies. Get copies printed and put a stick on them that say PROPERTY OF _________ and then take them to local coffee shops, etc. and ask to leave them there. Hell, even if someone steals the book, they're reading it, right

haha.
Personally, when I hit the movies, the last thing I care about it the ads on the screen. And this "hits" are based on what? Ticket sales? How many people are in the theatre while those ads before the previews are showing? How many are talking? Texting? Getting popcorn? If I had to dig out... I remember two ads from the last time I went... a dentist and a Japanese restaurant. Their names? Heh, good luck.
THEN AGAIN... for 6 months, that's consistent. Frequent goers, etc. may see the name and image over and over.
Another thought... in line with the neg. suggestion... talk 'em down to a month maybe. Offer $100 for one month to see the hits on your site, views for the book, and of course, sales.
6 months is a long campaign. And $500+ is a big price tag. How many copies of your book will you have to sell to JUST break even. And for that much, how many books do you have out? Let's say someone buys the book because of the ad... they enjoy it... what's next? Can they jump right back into another one?
For me, if I was going to have a big campaign like this, I'd have at least 5 books out. That way if you get someone to go to the site, they see books. And if they buy, they'll hopefully come right back.
Good luck with your decision - please let us know the results!
-jb
(And for me, views, impressions, it's all BLAH BLAH, because you just don't know. I have 100k plus impressions for a Facebook ad I ran. I got 90 clicks out of it... and 0 sales. Just be careful of the wording because the theatre probably up sells their viewers with ticket sales, etc. when you can't say for sure if all those ticket sales are in their seats when your ad runs...)