Instead of getting the whole HTML by Selenium (there are lighter tools for that, see Get html file Java), you can pick the right element with Selenium.
If you're using Selenium RC:
// assuming 'selenium' is a healthy Selenium instance
String divText = selenium.getText("css=div[align='center']");
or if you're using Selenium 2 (WebDriver):
// assuming 'driver' is a healthy WebDriver instance
String divText = driver.findElement(By.cssSelector("div[align='center']")).getText();
If there are actually more <div align="center">
elements, you can get them all:
List<WebElement> divList = driver.findElements(By.cssSelector("div[align='center']"));
// and use every single one
for (WebElement elem : divList) {
System.out.print(elem.getText());
}
The Selenium JavaDocs. In particular, you want to see WebDriver, WebElement.
And the Selenium documentation in examples. Read it.