Collecting Seed from an Easter Egg Plant?

I received the plant when it was only 10 inches high from a friend that lived on Manitoulin island in Ontario. That was in July of 2014. I replanted it into larger pot with potting soil and fertilizer. I put it in direct morning sun and shade in afternoon. In late September I moved it inside the four season room squirrels were looking at it.

It is now 3 foot tall and has 9 eggs on it and three eggs are turning greenish yellow. Was just wondering if any one could tell me when I should pick them to save the seeds for next year. What color should the egg be before you pick to save the seeds?

By Gerry