What is wrong with my SEO and website?

I have a small news site that has basically been a one-man show. I have hired one or two writers to write a few articles but I stopped after I realized that my website lacks authority.

The website is wivacoin and I have been doing all the work like writing articles and designing it using the Newspaper theme (it is built on WordPress). I only rely on the Yoast plugin for SEO. My domain score is 10. I have got a few good organic backlinks. At one point, I think I had an organic link from Forbes.

Here are my questions:

1. What can I do to improve my SEO rankings?
2. I want to hire a good developer to design the website to my taste. How much do WordPress developers charge (I am on a tight budget)?
3. Do I need to hire an SEO expert?
4. Can someone look at my website and tell me what is wrong with it?