Extracting Posts from database

I have a WordPress site that is bloated with 25K posts. 99% is junk. I want to create a new site and and extract about 30 posts from the old database and import them to the new one. It has been a while since I did this kind of work.

I would just delete 99%+ of the old posts and keep the database, but the installation has gone bad and it means I have upload the whole the 3.5G backup(not a problem), the problem is that even though I have a large high resource VPS, unarchiving that backup brings the whole server to a crawl and I get nasty ticket emails about hogging resources. So that is my last resort.

Any help would be greatly appreciated.