Joined: Sep 2009
Posts: 4,697
Likes: 2,039
From: Up
Bikes: Masi, Giant TCR, Eisentraut (retired), Jamis Aurora Elite, Zullo, Cannondale, 84 & 93 Stumpjumpers, Waterford, Tern D8, Bianchi, Gunner Roadie, Serotta, Serotta Duette, was gifted a Diamond Back
You will only need a new cassette if old one isn't appropriate for the type riding you do or if it is worn out, otherwise you can remove it and change it to the new wheels.
you should look for 32 or 36 spoke wheels.
truing a wheel isn't rocket science. read up on the subject and go slow (1/4 turns).