Make Columns Clickable and Sort Ascending/Descending

I have a script for MyBB. Right now it is missing the ability to order by ascending or descending. This makes it very awkward when things are not ordered properly.

http://www.2007rs.net/misc.php?action=monster

That is the link, I need the column names to be able to be clicked so they can be sorted based on the column names.

Here is the code:

http://pastebin.com/9jxs8ZVt

If someone could help me that would make it so much easier!