Settings problem (a DOH! moment)

I’m a newbie and I screwed something up in my settings on wordpress re: redirecting to another domain.

When I went to settings > general, I inadvertently put in the same domain name (the destination URL not the URL where the site is hosted) in both the wordpress address (URL) *and* the site URL and was too quick to press “save” to realize what I had done. DOH!

Now, I can’t access my oldurl.com/oldsite/wp-admin page and I see http://newdomain.com/wp-login.php?redirect_to=%2Foldsite%2Fwp-admin%2Foptions-general.php&reauth=1

Is there a way I can fix this? Thanks in advance…