Change page navigation link text


Using the Edublogs theme, I am having some trouble finding where to change certain areas of text:

I'd like to change the page navigation link in my header from "Blogs" to something else.
Where would I find this code?

Gavatar link text (under Blogs tab)
I'd also like to change the link text within the blogs tab underneath each gravatar image
from "Visit Blog" to something else. Whee would I find this code?

Homepage sub-title
"How Can Help You?"

Sidebar title text
"Latest News"