In many cases, the theme can only help or hurt SEO just a tiny bit. Sure, you can use SEO and sitemap plugins to help but my initial thought is that there are two big factors in why search engines aren't driving a lot of traffic to you at the moment:
1. You are in business/technology niche, which is very competitive. Any site that's been up for only a few months typically not be anywhere near the top of any search.
2. You do not have a lot of engagement yet. Your articles only have 0-3 comments each.
The good news is that you're producing a lot of unique content. In the near term, you could also focus on generating more activity on your site.