It all depends on your budget and the amount of time you have really.
I have a 1.0lx myself and if I had the money, the time and I happened to know the right people I'd probably look at getting a 1.3 engine from a scrappy and look into turboing it. If your Dad is a mechanic then thats a big advantage.
The advantage to this would be that you can re-fit the 1.0 engine thats in the car at the moment without much hassle if you want to revert back at any time and if you do end up screwing something up, it's only £100 or so for another 1.3 engine and you can just do a straight swap if you decide not to go down the turbo route.
Personally speaking, I wouldn't go changing to a 1.6 or 2.0 as there seems to be a hell of a lot of work involved with structural parts of the car and the electrics that you really don't want to mess up.
Thats not to say putting a turbo in isn't a lot of hard work, but from what I've seen so long as you understand how the turbo works, can weld a custom manifold and can pay someone to mess about with the fuelling, ecu, etc then it's an option. The amount of strengthening the engine would need for this is dependant on how much boost you would want to run I guess. I would speak to someone like Kristian or Ed if you seriously want to go down this route though as I really don't know much about it.