Help to make a proposal.

First of all, I want to clarify that I am not a native English speaker, excuse me if I am not clear.

I have a website 15 months ago and I have and content is 400 dental clinics , I show contact location , some lines of text, map and little more, also about 50 articles on the subject.
I have more than 800 keywords in top 50 some very important in top 30 and many in top 10. Canada and the United States are the main contents of my site and visitors.
Here comes the request for help, I only have Adsense and it is very little traffic, 99% organic that makes 1000 visits a month, I want to take advantage of this moment in which the clinics do not work to communicate via mail and comment on the benefits of being on this site and that for $ annual can add content and a link, they believe it may be viable ... I can not visit personally or speak it because it is not fluent in my English. I accept critical suggestions.
Thank you

Sounds you need to contact a copywriter to draft you some sort of message you can blast to these clinics.

I advise you to contact the clinics in the pages receiving the most traffic already. Those will be easier sells.

If I already have a small database @ and I will customize the message. I am adding UK clinics, I will comment if I have a response. Thank you