The problem is that your page uses a frameset. You should tell your webdriver which frame to use when it will search for your element. So try this:
driver.findElement(By.name("username")).clear()
driver.findElement(By.name("username")).sendKeys("john2013");
driver.findElement(By.name("password")).clear();
driver.findElement(By.name("password")).sendKeys("john2013");
driver.findElement(By.cssSelector("input[type=\"image\"]")).click();
//switch the driver to use one of the frames on your page. Potentially wait for a bit till the page is loaded
driver.switchTo().frame("mainpanel");
driver.findElement(By.xpath("//*[text()='New Contact']")).click();