moving: can't log-in in either ole or new site

I am confused and need help.
My fault that I didn’t read this article http://codex.wordpress.org/Moving_WordPress before attempting to move my site from TMD hosting to GoDaddy.

I backed up the database and WP files. I transferred the domain to GoDaddy (is that relevant?). I created a database at GoDaddy and imported the sql file. I uploaded the files and edited wp-config.php.

I got to see the shell of my site with “can’t find the page” message at the new URL. There was an error message at the top (I didn’t copy is but it said something like “can’t edit header and mentioned seo-all-in-one.)
I was able to login. I foolishly changed “WordPress address” and “Site address” to the new ones. After that, I can’t log-in anymore. I redid the whole process but nothing works. Then I found that the old site is broken (no header image. I can’t log-in. FAQ and ABOUT link point to new URL1)

It’s clear that I don’t understand how WP works when changing a domain. I am thinking of restoring the old site with my backed up files, then follow the article that I mentioned. Would that work? Should that work? Any advise is much appreciated!

Old site: http://www.naminoriita.com/
New site: http://nakayumi.com/naminoriita/