In the backoffice click users | username | check notifications box.
Also on the blog page itself on the sidebar look under the admin /login links for "subscribe".

I have had a look on the online demo versions on here and have not been able to find the areas that you have suggested.

The demo site doesn't let you edit the admin user account, but if you create a new user you can see the checkboxes for email notifications. That's for when people comment on your post, but to get email notifications when any post or comment is made to any blog, you can use the [url=http://demo.b2evolution.net/v-1-9/blogs/index.php?login=admin&pwd=demopass&blog=2&disp=subs&redirect_to=%2Fv-1-9%2Fblogs%2Findex.php%3Fblog%3D2%26paged%3D1%26page%3D1]Subscribe form[/url], like mrdav said.