Can't log back in to WP

Hey,
I’m a VERY new user of WP and when I was logged in and on the General Settings, I changed the WordPress address (URL) and the other URL
I guess I thought this would make the new WP-based site go “live” under the new URL(and I was following instructions on how to move my site from exampleURL.com/home to exampleURL.com). Instead, I was immediately logged me out of the control panel and now every time I try log back in to my WP dashboard, I get a nice 404 Page Not Found

I am using ipage as my host.

Now that I cannot access the dashboard, I cannot make modifications to my WP site. Help! …and thanks for your help!

Any answers please dumb them down just in case ;).