The site below isn't exactly what you are looking for, but I think it will help. When you get the cloth all measured for length, width, and drop as for a rectangular table, you'll need to shape the ends.

At this point, you'll probably want to make a paper template of the shape of the ends of your table. (Your table might not be a perfect half-circle at the ends as the round tablecloth example assumes.) Then use the template to shape the ends of your material.

To make a template, get some really large paper - LOL! - you could tape pieces of newspaper together, or use old gift wrapping paper taped together. Then place the paper on top of your table, overhanging both edges and one end a by at least the amount of your chosen drop. You'll then be able to feel the edge and draw a pencil line there. The next step is to draw your CUTTING line.

Here's an example: say your chosen drop (including seam allowance) is 12 inches. Then you need to measure out from your template end line by 12 inches all along the oval end line shape, and draw a NEW line. The NEW line will be your cutting line.

If all has gone well, your cutting line should come out to meet the width lines (width + drops + seam allowances).

Try drawing a little sketch of your table top on paper, then sketch around it the lines of the tablecloth with the width, drops, and seam allowances. I think the oval end template will all make sense then.

Ask again here or at the Sewing Forum if you need more info. The Sewing Forum has a lot more traffic than this one and the ladies there are all experienced at sewing!

Good luck!

Here is a link that might be useful: Making Tablecloths of Any Size