[need help changing header.php to html file.]

i need help changing the header.php file to html file. i want to header to have a few link instead of picture file.
where and how can i change that?

question 1.
where can i change that? under which file?

question 2.
need help changing that word TOP to HOME, where can i change that? whihc file is that?

question 3.
need help changing that word, Contact Us & Shipping & Returns to About Us. which file may i go to inorder to change those words.

question 4.
can i add an extra box there? if yes, how may i do that?

[url=http://img181.imageshack.us/my.php?image=oscommercehv2.jpg][img]http://img181.imageshack.us/img181/9180/oscommercehv2.th.jpg[/img][/url]


Thank You for reading my post. waiting for ppl who know to help me. Thanks again.