KO'd my blog somehow

Ok here goes.

I signed up for my wordpress blog through my Yahoo web hosting as an add on to my website.

Once I started using it, I liked it so much that I wanted my WordPress blog to be my homepage and my website.

So I went under “Settings- General” and changed the two URLS for “WordPress site” and “homepage if directory other than” to the index page of my site-
http://www.wbduvall.com/index

This totally tanked my website! But worse, now I cannot log into my wordpress blog.
A strange, primitive looking version of my wordpress sign in comes up- http://wbduvall.com/duvallblog/wp-login.php
and when I enter my blogname and password, it sends me directly to the E404 message of my site.

I was able to get my original homepage back my simply republishing my site. However, now the original blog location http://wbduvall.com/duvallblog/ comes up totally crazy and looks nothing like the theme I had and if I click anything on it, it takes me straight to the E404 page.

Since I cannot log in, I cannot change it.

I couldn’t even use my blogname to log into this forum because WordPress.org website would not recognize it or says it doesn’t exist.