WordPress admin area

I bought a new domain name and in the admin area I changed the URL ect to the new domain name, which I should not have done at this stage.

However as the old domain name still stands I wanted to go back into the admin area to fix what I had done. However when I go to log in it redirects me back to wordpress.com admin.

I do not know how to go about logging into the www.remarpro.com admin area to fix the problem.

This is quite urgent as my blog is not displaying correctly.

Thanks for any help.

Susan