Disabled test domain after real domain was re-pointed, links are still on test

I built a website in WordPress on a test domain that was assigned to me. When I re-pointed the actual domain to it, in order to make the website accessible from the real url, and switched off the test domain, it turned out that the images and js files etc. had the old test domain at the beginning and didn’t switch over to the actual one. As a result of this, they stopped showing up. It wouldn’t be a problem for me to find and replace all test domain links with the actual domain name in the page and post content but when I try to log into WordPress it redirects me to the old test domain URL.

The website is here http://www.evidenceit.com/

Is there a way for me to change all the links in the head of the URLs that refer to the old test domain, to the new one? Since I cannot log in to WordPress I would have to do it remotely – is this possible?