yeah you'd need to get some flanges made up and pipe bent, then cut the pipe the right lengths and weld it all together, way less hassle to just get one of the stainless manifolds off trademe if you chose to go single.
for single turbo conversion you will need:
a turbo, which you told me you have and from the sound of it its not massive so it would probably be alright
a manifold
an external wastegate if the turbo doesnt have an internal one, or if you just want that cool sound
a blow off valve (you could be cheap and use the stock one, just make some kind of adapter to fit it to your new...
intercooler piping because the standard piping aint gonna fit now
intercooler i guess thats kinda optional you could try to use the stock one, but those are pretty crap so you should get rid of it anyway
theres a fair bit of labour in there, and you would want to get your air/fuel ratio checked on a dyno to make sure everything is sweet