Should be doable. Bear with me here. A few steps:
First, create a navigation menu.
- Go to Appearance > Menus
- Create a menu, call it whatever you want (e.g. Navigation). Enter a name and click the Create Menu button.
- On the left-hand side, select the Pages you would like to add to the navigation. I suggest copying the navigation you already have on your site. Drag and drop the links in the order you'd like them.
- On the left-hand side, click Links, enter your blog address as the URL (http://bluemetros.wordpress.com/) and "Home" as the link text. Click Add to Menu. Drag that up to the top of the list so it's first.
- Click Save Menu.
- Click Manage Locations tab (top of the screen).
- There should be a theme location called "Primary Menu" or something similar. From the adjacent Select a Menu dropdown, choose the menu you just created.
- Click Save Changes.
This should replace the navigation menu at the top of your site with the menu you just created, including that link to the Home page. Whenever you want to update the menu, just go back to the Appearances > Menus screen to update it.
Hope that all made sense... really wish I could do a little illustrated guide or something. :D
More details on menus: http://en.support.wordpress.com/menus/