Change category button in post

Hi everybody,
i need help. i have three categorieswith ids 1,2,3. while i am logged in as admin at front page i see "edit" button under every post. i want this button to change only category of post. now it has href value <strong>http://mysite.com/wp-admin/post.php?post=20&action=edit</strong>. editing post.php is very complex with its arrays. i need value like this http://mysite.com/wp-admin/post.php?post=20&action=edit&set_category=$category+1 to edit only theme files. please give me the right value for this.