Comment_form customising issue

I have been trying to figuire this out all evening and can’t make sense and am not really sure what to search for on search engines. I am pretty much a noob at wordpress. I know HTML, CSS and I can customise a basic WP template, it’s just this last bit on the comments area that I need to customise which I am having trouble with.

This is what I have in my comments.php in my theme

[code moderated according to forum rules - please use the pastebin]

This is how it looks on my wordpress blog: http://millajovovichfan.com/lucinda/?p=23#comments

I have managged to customise the comments_list with a callback that I customised in the functions.php file which is in the themes folder.

I have been trying to do something similar with the comment_form because you can see how it looks at the moment - the default look.

So, my question is do you also use a 'function thing' for this, like you do with the comments_list ? because the way I managed to code that to how I like is because I used the default function for the comments_list and took the tags(I don't know if that's what theyre called, but anyway - the codes like '<?php comment_text(); ?>'

This is how the area of my functions.php for the comments_list looks

function mytheme_comment( $comment, $args, $depth ) {
	$GLOBALS['comment'] = $comment;
	switch ( $comment->comment_type ) :
		case '' :
	?>
						<!--comments--> <tr><td class="maincontent_postcomments"><div>
<div class="comments_datenameedit"><?php
/* translators: 1: date, 2: time */
printf( __( '%1$s', 'twentyten' ), get_comment_date(), get_comment_time() ); ?></div>
<div class="comments_datenameedit"><?php printf( __( 'Comment by %s' ), sprintf( '%s', get_comment_author_link() ) ); ?></a></div>
<div class="comments_datenameedit"><a href="http://"><?php edit_comment_link( __( '(Edit)', 'twentyten' ), ' ' );
?></a></div>
<div class="comments_comment"><?php comment_text(); ?></div>

<div class="comments_datenameedit"><a href="http://"><?php comment_reply_link( array_merge( $args, array( 'depth' => $depth, 'max_depth' => $args['max_depth'] ) ) ); ?></a></div>

</div>

						</td></tr>	<!-- #comment-##  -->

I get confused because in the codex files it says that the source is in wp-includes but I need to have the customisation of it in the theme folder obviously - I just don't know how to do it.

Because I have customised the rest of the template, I'm sure I could learn how to do it.

Thanks for any help!!