bangers,
You have to use a paint program to create the curve. If you will e-mail me at yvonneh@site-blauvelt.com, I will send you samples of right (top and bottom) and left (top and bottom) you can edit these to the colors to match your website and you would place them in your table cell (top align and right or left align respectively). This is the only way to get a curve. Some people draw a circle and then crop all but what they need. You have to make sure that the inner portion of the curve matches the color of the table on the inside and the outer portion of the curve would match the outer portion of your page or table/graphic that you are using.