What does the Downloads Remaining number mean?
The "downloads remaining" number is the amount of times remaining that you can download the product from your order. For example, if you downloaded it once but something happened to it, (it didn't download properly, or it was deleted accidentally...any number of things) you can log back in and download it again that number of times, for the amount of "time remaining" on your order. The downloads remaining does not mean that you can only use them that many times, it's mainly there for backup in case you need an extra download.
There is no way to "save" your remaining downloads, once you have your item downloaded and unzipped and saved you should be ready to scrap with it! :) (People often save a backup copy of the zip file, to a CD or other source.)