I have not used Selenium 2. Selenium 1.x has selenium.getTable("tablename".columnNumber.rowNumber)
to reach the required cell. May be you can use webdriverbackedselenium
and do this.
And you can get the total rows and columns by using
int numOfRows = selenium.getXpathCount("//table[@id='tableid']//tr")
int numOfCols=selenium.getXpathCount("//table[@id='tableid']//tr//td")