WordPress Admin Problem

So im trying to make wordpress read at the main url while the files are in a seperate folder.

In my admin I accidentally changed something I shouldnt have in Options > General. It was the path to wordpress and the path to the blog.

I know how to fix that problem. But what I dont know is how to get to the spot to do it. Being I changed that option to something else, the entire admin is down because its trying to read from the wrong place. Anyways my question is this.. how do i replace the defaults i had or how would i go about getting back into the admin and resetting everything.