text in table cells not centered as in headers

Answer 1

First of all you forgot to close the td after the first input.

 <td class = "one"><input type="text" name="quantity1" value=""/></td>

You can add this css to make them center

td
{
    text-align:center;    
}

Have a look on this EXAMPLE

Answer 2

You can add this to your css:

td.two, td.three {
  text-align:right;
}

You need the td prefix cause your th is using the same css class.

I hope that helps.