If you're boiling the water, letting it condense and only generating power from it running downhill afterward is horribly inefficient. You should use the expansion of the steam from the boiling to power a steam engine.
(This has the disadvantage that you're working with high pressures and temperatures, with a resulting explosion risk. But you can mitigate the risk by having only a small amount of water in the system, using only pipes rather than a big boiler or storage for above-boiling-point pressurized water, and of course a safety valve.)
A tracking dish - a two-dimensional focus - lets you generate superheated steam and get more of the energy from a given amount of light-collecting surface turned into mechanical power. But it also gives you extreme temperatures (i.e. it can melt metal if the water runs out). And tracking the sun minute-by-minute means more complexity and moving parts.
A parabola trough - a one-dimensional focus - only needs to be adjusted for the season. It will generate "process steam" - boiling the water but not heating it too far beyond the boiling point. This will drive a small steam engine. You get less power from a given collection area because the collection temperature is lower. But if you have the land for it it's much easier to build a large collector, and this can make up for the inefficiency.
In either case, after you've run the heat through your engine you can use it for other heating uses - like heating your house water or your house air. The amount of heat you'll get is proportional to the area of your collector and is not affected by the type of focus, only by how well the object at the focus absorbs light. Running it through an engine converts SOME of its energy to mechanical power - which will go back to heat where you use the power - and so the dish system might have a smaller fraction of the heat it collects left for dumping into heating systems. But even that one will only convert maybe a quarter of the heat to mechanical/electrical power - if you did it REALLY well - with the other three-quarters or better coming out as heat you must dump or use as heat, and the tracking improves over the non-tracking trough by about that amount. So figure on your heating capacity being essentially just proportional to the area times the number of solar hours at your location and you should be about right.
