Photoshop and web design?

First of all let me say I hope this question makes sense and also that I hope I can post it here.

Secondly, here is an example of what I am talking about, (I made it using various photoshop tutorials)

Ok, here is the questions. [Could you please imagine some buttons going down the right hand side]. I made this in photoshop and am now wondering how make it interactive (buttons changing colour on mouseover) Do I have to slice it up or something and then put it into dreamweaver?

I would also like to have Different text appearing in the large, light grey area on the left when different buttons are pressed?

I know all these things can be done because I have seen things like this a million times. I can use dreamweaver a little and know how to put tables into a pge and buttons into the tables - no problem, but this combination of photoshop and dreamweaver has me very confused.

I hope you can help me out or point me in the right direction to tutorials.

Many thanks.