I just had to throw in my own version of get more traffic.... get more traffic. 14 days later, how are you doing?
It's quite simple to hit $100USD, even with one website. I'm about to hit it with a site, and it's been 3 weeks since I started it. I believe it's all about the link exchange and SERP.
I still remember I have about the same amount like yours now in my very first month. As time goes, you will learn more on SEO and ad optimizing, and same goes as your AdSense earnings. Good luck!