Learn XHTML/CSS first off, this is basically making your design into a coded page.

Next learn a server side language..PHP is probably best since it's easy, free, and very widespread.

You can finish off learning Javascript.

Thats what I recommend.

Some notes:
Javascript is not a server side language like previously stated. It's client side meaning it is interpreted by the clients computer more specifically his browser.
AJAX is not a language it's just a technology within Javascript that you can use to make your applications more usable and for lack of other terms..cooler.

To learn all this it all depends on your learning style. I suggest picking up a few books from Amazon..read the reviews etc.. and pick one out. Or you can just follow online tutorials.