Some of the snippets you are using are available in the Resource Repository. For example Prev/Next is a common one and so is NewsListing (I think this was the actual predecessor to Ditto).
As others have said there is not much that you should not be able to replicate with a little effort. I suggest that you get the design part (xHTML/CSS) all ready and then match the snippets to the new design specs.
Also I would install a practice copy of the site on a local server and then: 1) update it to the lattest version, 2) make the changes to the snippets you used to get the new snippets working accordingly. This way you can play around and figure things out as it figures to your content in a safe environment (away from the live site).
