Gearbox problems, 1993 MK3 Golf?

I have a 4 speed box and was having problems with 1st and 2nd gears grinding, the gearbox oil was topped up and the following day I was able to get the car into reverse but 1st and 2nd just wouldnt work, currently I am unable to use 1st gear, 2nd works with some force but sticks, 3rd, 4th and reverse are fine. Can this be fixed or am I looking at getting a whole new gear box???