Do you want to build a new wheel yourself?
If so, then as you say, you'll need a hub, a rim and some spokes. If your wheel has a 700 tyre on it, it's a 700 rim, not a 26". Spoke length is critical - but see below.
The important thing is that the hub and rim have the same number of spoke holes. You can find instructions for building a simple wheel in many places online. I've used
Sheldon's to build two or three wheels now. Building rear wheels is rather harder than fronts.
If you're not planning to build it yourself, and you want a bomb-proof wheel, my advice would be to find a shop that builds wheels and has a good reputation. Go along and talk to the wheelbuilder, explain how your spoke breakages occurred and take his or her advice. Rather than thrust your choice of hub, rim and spokes into his hand, it's probably better to take his advice - builders often have preferences for these. A reputable builder will guarantee a wheel he's specified and built himself, but may not stand by a wheel built with components that weren't his choice.