Skeptic, it's very important that you take some time to understand what the theory of evolution is really about.
Here's a point which should help clarify things. Each individual genetic changeis like a penny, thus 'microevolution' is like collecting a lot of pennies. Each one is practically worthless on its own. But when you get enough pennies, you can buy something with them. In effect, the individual genetic changes add up and can be exchanged for a larger genetic change.
Now, when these organisms reproduce, they bequeath any changes they've managed to get to their offspring (as well as a number of the unspent pennies). Like an inheritance. Of course, each offspring inherits different things, so they earn their own pennies and exchange them for larger genetic changes of their own.
Now, another thing to remember about the larger changes is that they're not finished structures. It would be better to think of them as larger units of money, which can themselves be exchanged for larger units of money. Not only that, but there are many different currencies - so an organism might get a cent, then get a yen, a franc, a mark, and so on. But as they collect them, they can exchange them for larger units of money and ultimately trade their way up to very large changes - which is 'macroevolution'.