Appearance of showcase template

I have my site to be set up so that my blog is a page called “blog” (instead of it being my homepage). The only way my posts would show up on my blog page was to change it to use the showcase template. The problem I am having is that the posts start in the middle of the page instead of to the left. So I have this large area of blank space to the left of my posts.

My home page is set up so that my widgets are on the right. I do not want my widgets to show up on the page I created called Blog with my posts. I hope that makes sense. My site is under maintenance mode so it wouldn’t make sense for me to leave my link.