need help please

hi guys i have a uk base model (http://www.google.co.uk/search?hl=en&sa=X&oi=spell&resnum=0&ct=result&cd=1&q=model&spell=1) premacy GSI special (http://www.google.co.uk/search?hl=en&sa=X&oi=spell&resnum=0&ct=result&cd=1&q=special&spell=1) edition 1800cc and its a manual gear box, gearbox will not select 2,4,Reverse gears, can any one help????
not sure if i am puttin this in the right bit

all help welcome thanks strang

i can suggest you the list of the gearbox dealers or manufacturers you can get good advice from them