This as has been said is not a cheap option if asking someone else to do it for you.
A quick budget for a single turbo conversion: (based on you sourcing the parts and handing them over to be fitted)
Turbo - £1000
(400-600 including intercooler,pipework,gate,etc)
Exhaust manifold and downpipe - £1250
(<600 manifold,??? downpipe)
Waste gate - £500
(Included in turbokit)
Low compression pistons MLR head gasket - £1000
Intercooler and pipework - £400
Fuelling system and tuning - £2000
(1000 if you're lucky and search well,or know(join lol) some college course boyracers. lol)
So you can see not a cheap option, but you will see 4-500bhp
(300+bhp) at the end :bannana:
Unfortunately once you do this, the above costs will only be the start.