restoring posts after botched upgrade

I posted earlier about the way my numeric permalink sequence got screwed up when I upgraded from 2.2.2 to 2.5.1 and some Static Pages were somehow converted into Posts and given numeric permalinks, changing the numbering of the posts. (The guid listings in the datbase were unaffected, but the ID numbers were altered.)

Having gotten no replies, I’m assuming the idea of manually altering the permalinks now is a non-starter and I need to reconstruct the posts from my backup.

I’m unclear what’s the best way of doing this. I have an SQL backup of the 2.2.2 database but the table structure in that version differs from 2.5.1. I also have an Export backup of the posts done just before the upgrade.

Can I use the Export backup? If so, what is the best way of getting rid of the currently misnumbered posts before doing that? Thanks.