a standard rebuild is around 4000+ then if u add a lil flavour to it, maybe a turbo kit (just a lil one) then around 10k (this is with all brand new parts and nothing chinese etc)
ur best bet is to speak to ur mechanic and see what he says.
if u dont have a mechanic there i already mentioned one further up the page who i will only ever use but there are many around melbourne who are very good