lost ability to log as admin

I got all my theme set up and ready to place it on my site, I installed wordpress in a sperate directory to work on the theme. when I was done I went to the setting–>general and changed the url path from http://my_domain.org/WP to http://my_domain.org. now I cant even log into admin to change it back. what will happen if I re-install and overwrite wordpress same directory, or move all content from folder/WP to root? in any case with is the best solution without losing my theme setting.

Thanks

Chris