Id carry on with it. Get a HKS 2mm head gasket, yes its £190 but its built like a brick shithouse or cometic. The clutch depends on what you get and if you can do it yourself.
Radiator is a breeze to change maybe tight being a turbo but is worth fixing.
Handbrake i could'nt see being that much.
sump is easily replaceable
As for the breaks maybe look round for some on here, depending whats wrong with yours.
Head gasket and clutch would be worth doing at the same time, especially if you take it to a garage.
sump you could do yourself one day at a weekend.
Never worked on handbrake cables so cant comment.
Turbo pipe depends what one, boost or oil/coolant feed? Either way replacement one isnt going to be a awful lot. A decent machining firm should be able to make up a new turbo pipe.
You've spent some to get it this far its worth getting these bits done, even if it takes a few months.
Ive just spent £1800 all in getting the engine rebuilt drained my bank doing it but, way i see it there isn't many almera turbos floating about. Its nice to have something a bit different that you've put some time into. Its up to you at the end of the day. With what needs doing to it. The headgasket and clutch are the only real things that may require some wedge and time. The rest, parts and fixing should be straight forward enough and do able reasonably cheap. Stick with it
unk