First Question-
What is your goal for upgrading?
Is something wrong with your wheels, or do you just want a spare set mounted with different tires?

The RIMS (not wheels) on the bike should be exactly like these- For disc brake, you need disc brake hubs.
http://www.amazon.com/Avenir-Joytec-.../dp/B004AIE3O2

These rims would handle a 28MM tire and probably as small as 26mm, although that's starting to push it.

Disc RIMS don't need a brake track.