Help needed regarding Time to First Byte!

[l3ogdan]

Hello,

After spending some time reading documentation and speed optimization tips I managed to improve the site loading time. Unfortunately, it seems like I`m stuck at this point, where I don`t know what else I could do in order to reduce the Time to First Byte time. Here are my last test results:
http://www.webpagetest.org/result/140603...1/details/
The website is custom php with a small MySql database associated. I even generated static index.html page for testing in order to eliminate the concerns related to MySql queries, but I didn`t notice any improvements regarding TTFB. The website is hosted on a reseller package at Hostgator.
I kindly ask for an expert opinion regarding this matter. Basically, I would like to know what is the root cause of this problem: the hosting package or the website code? Any help / advice is highly appreciated!

Thank you in advance,
Bogdan