500 internal server, problem loggin in to old site

Hi,
I built a wordpress site at lets say testsite.com and wanted to move it to golive.com which is a different webhotell and domain, I didnt get it to work I got a 500 internal server error I’ve contacted goDaddy where it will be moved to so I’m waiting for a response, however I did mess up a bit cause I cant get into the dashboard anymroe on testsite.com because I changed the website to golive.com under settings, I know not very smart but is there a way to fix that? when I upload and work with the files I use dreamweaver.

I hope this makes any sense and that someone can help me.

Thanks

http://wordpress.org/plugins/duplicator/