Quite by coincidence, I changed a clutch and gearbox in my Uno only last weekend!
Mine is a FIRE engined Uno, but the principles are the same.
It's a tedious job rather than difficult, took me the better part of a day to do it as I was very thorough and did a few other jobs as well.
The way I did it was to raise the front of the car on stands, remove the gearbox and drop it out underneath. Even on a turbo, you should have plenty of room.
You have to drain the gearbox oil (if you have to remove the driveshafts the oil will come spewing out of the gearbox driveshaft housings!), remove the battery for more room, disconnect the clutch cable, remove the reverse light switch cable, disconnect the gearchange linkages (they just 'pop' off their sockets), remove the starter motor, undo the top of the front hubs from the struts, remove the track rod ends from the hubs, remove the driveshafts, remove the gearbox brackets (front and rear on a FIRE Uno), undo the gearbox and drop it out of the car.
You also need to support the engine before the gearbox brackets are removed by supporting it with a stand and a block of wood under the sump. You can also use a support brace (if you can get hold of one) across the front wings and support the engine from above instead.
Biggest problem I had was getting the driveshafts out and back in again. My FIRE Uno has a turbo roll bar fitted which gets in the way. They can be removed with the roll bar still fitted to the lower suspension arms, but it is awkward.
You should be lucky though, as the turbo has a split driveshaft on the drivers side, and you can (I think) unbolt the outer section and leave the inner section still connected to the gearbox. Makes it that much easier.
Instead of a crane like SuperUno suggested, you could hire a dedicated gearbox jack. This goes underneath the gearbox and is strapped into place, and as it is on castors you can the roll the gearbox around underneath the car.
Before you do the job make sure you read up the procedure in the Haynes or Porter manuals. They are quite clear on what needs to be done.
I'd also suggest having someone to help when you remove the actual gearbox from the engine and also to help you guide the new one back into place. A second pair of hands makes a bit difference as it is quite a heavy unit.
Oh, and whatever you do, make sure you fit a new clutch! You'll see how awkward changing a gearbox is, and if the old clutch fails a few thousand miles after changing the gearbox you'll be kicking yourself :bang:
As for changing the clutch, you need to centralise it when fitting the new friction plate and pressure plate. There are some tools that can help you do this, though the FIRE engine doesn't have a spigot bearing in the crankshaft for the older style of tool. You need the one that can centralise the the friction plate to the pressure plate while they are off the car. You leave the tool connecting them together, refit the clutch to the flywheel and when it is bolted up you then unscrew and remove the centralising tool. Draper do one that you should get from a decent motor accessory store.
All in, it's not a very nice job but doable at home with the right tools and some time. I'd also recommend you try and do it in a garage rather than outside, as it can take a while. Nothing worse than doing a job like that and then it starts raining...
Anyway, good luck with the job! Are you going to get it done before the ACE cafe meet next week? Maybe you could bring the turbo down before you do the gearbox swap so we can all see it first!
Chas
i know it would be easier in the long run to take the whole engine out but its so much more work as far as disconnecting everything etc and laveling everything up. so much more to go wrong rewiring it all back up etc and reconnecting all the bits and bobs 
