One thing, don;t think of them as being imported in any one particular order.
The order of the images is completely fluid, you can change it anytime you want to suit your needs at that particular moment.
As Léonie showed you select the order you want to see the images in by selecting the item you want to sort on in the pull-down.
The only time fluid sort order can be a problem is when you export groups of images. If you put the images into a particular order in Aperture when you export them and view them in the Finder the order they are in may very well be different. In this case you could give names to the images that include a sequence number or index.
Then when they are viewd in the Finder they will be in them same order they were in in Aperture.
regards