Fixing post display order after import

A WordPress photography blog crashed during an upgrade and I was able to restore it partially, but many problems still remain. I exported the content and set up a new blog and imported the old pots. Now they appear in ascending order, instead of descending order. In other words, although I want the last post to appear first, it’s the first post that occupies that position. How do I fix this?

I also need to integrate posts from one blog into another, but I do not want to disrupt the current order of the blog into which they will be imported. Is there a way of doing this?