the first part, removing #access from its current hook, you could find with a simple search of the forum:
// Remove default Thematic access
function remove_thematic_access() {
remove_action('thematic_header','thematic_access',9);
}
add_action('init','remove_thematic_access');
the second half depends on where exactly you want to put the menu... my first thought it to add it the thematic_abovemainasides hook like so:
add_action('thematic__abovemainasides','thematic_access');
however, it will look like crap until you fix the CSS. if you don't like the standard way the access outputs the menu then you can write your own child_access function.