How To Get Quality Leads for Kindle Niche?

First, here's my story...
I've recently made a Facebook page in the Kindle writer's niche. It's got over 400 likes now and they're a bit active. I've tried to post a few affiliate links to the page related to the niche, but I got no sales.
So, I've a mailing list. I'm using Aweber, and I've already started the list and the opt-in forms.
I've posted the opt-in form on the Facebook page twice. I'm giving away a free copy of my "Kindle Success Formula" when they sign up. Strangely, I've gotten 20 displays from the opt-in form and only 1 submission, according to Aweber. This doesn't seem right because I've gotten a few more sign ups than that, and a few shares on the Facebook post. Is Aweber sometimes not too accurate on this?

I've also imported the emails from my product sales on JVZoo. I've imported around 100 emails and gotten somewhere around 20 sign ups. Currently, altogether, I have 28 subscribers to my list.

Here's My Question:
How can I get more subscribers besides my Facebook fan page and product sales? I only want quality subscribers!

Also, here's a link to my Facebook page if you can give me any recommendations on it, as well as my opt-in links that you can find here: www.facebook.com/dailywritingtips4kindleauthors