Homepage custom, blog on a page

Hi

I have created a theme where the homepage with usual header/footer and the content(index.php) has some ajax in. All my pages (except homepage), categories and post pages have a left and right sidebar.

What I want is for my blog to be under a page, i.e. ‘blog’ but allow my custom index.php be the homepage.

If I change settings in ‘admin/general settings/reading’ where you can have a page as a homepage and then have your posts appear in another page within the navigation, i.e. home about blog, it just makes the page I designated as home, as the homepage.

Is there a way I can have this happen without WP calling the created home page and just letting me use my custom index.php

Thanks for any help offered.