Editing a 650Mb file is unpractical, whatever method used.
Better import it into the database first then see about edits.
Just found this in version 6.0
MySQL :: MySQL 6.0 Reference Manual :: 12.2.7 LOAD XML Syntax
only glanced over it so not sure it can handle your situation.
Speaking as a developer i would create an application to do it (or have one created), if you just need to map the xml tags to mysql tables and fields then it should be possible for a budget less than 100$
You can try a site like rentacoder, getacoder, getafreelancer, etc... with a bit of luck you'll find a guy to do it for 10$.