2 Different Main Index Files?

I’m hosting my blog on Yahoo and my domain name is thatshotblog.com. I have it set so that my homepage is my blog. However the rest of my blog files are housed at this address: thatshotblog.com/blog And for some reason my sidebar is different in thatshotblog.com than the one on thatshotblog.com/blog. I want thatshotblog.com to look like thatshotblog.com/blog. Why are the different and is there a way to make them the same file or at least update the same? I’m very confused and need help, please.