Threre is an old web designer saying that goes like this...
You cannot polish a pile of dung, but you can cover it in glitter.
In order for this site to get more visitors WITHOUT making a changes to the typography, layout , colour scheme, navigation or even the actual content you have to fool the Google search engine into believing that the site is more popular than it actually is.
This is known as 'Black Hat' SEO and involves things like filling the desription and keyword meta tags with popular search terms, spamming blogs where visitors can leave comments, directory (link farm) submission, placing adsense inside iFrames to boost page views and asking friends and family to click on adverts to name but a few.
However: if google catches you doing any of the above then you risk the domain being forever removed from ANY search results and you lose any money gained in the adsense account.
Grey Hat SEO only slightly naughty
Backlinks are of course highly prized but no sensible webmaster will want to place a link to your site because it would probably hurt thier own sites existing ranking.
So create yourself between 200 (more is better) simple websites each with a different domain name and place a backlink on each of these to the site you wish to improve. This is an old trick of website template makers and a few website designers.
There are no miracle cures or secret source codes.
[PS double posting will not help]