terrible bottom end knock... help

[Ahmed_1990]

hay, names ahmed, apprentice mechanic 2nd yr, now thats the intro out of the way heres my problem

i own a 1990 suzi vitara, g16 carb engine.
it has a knock from the bottom end of the engine, the guys at work tell me its the barrings, my questions are

1) how long will it last before it blows, lol
2) is it hard to pull the barings out and replace em?
3) how long will it take to replace them, and
4) where can i find barrings for a good price (even tho ill most likely get trade price)

will it be worth having the car out of action for 3-4weeks to repair it, or should i try and sell it?

help please