I think you may be looking at an issue of ranking in SERPs all wrong.
Search engines do not rank websites, they rank individual web pages for individual keywords. Odds are you already have numerous first page rankings on those 40 pages that you have created. The problem is that you haven’t gotten any of those individual pages to rank for the one keyword you are primarily targeting.
I would change your strategy slightly to include long-tail keywords that include your primary keyword as a root. Select long-tail keywords that have a bit of traffic but little competition. Those long-tail keywords will be relatively easy to get onto the first SERP. This will not only give you targeted traffic, but it also goes a long way toward building authority for your primary targeted keyword.
Include a link to your homepage using your primary targeted keyword as the anchor text on each of those pages targeting the long-tail keywords you are ranking well. As you build your homepage’s authority for your primary keyword it will begin to rank higher in the SERP.