Should i stay at the job with torn cartilage in right knee

Hi
Iam a 33 year old male and I do keep fit walking etc..
My 2 knees have been very sore these past few years.In the last 3 years my right knee would give a load "clunk" when I kneel down or straighten them,leaves it very sore,they sound like knees of an 80 year old.both knees are very sore in the morning.I had injections in my left knee a few years ago,but I only got short relief.
I had an mri scan done on my right knee showing a partial tear in the inner cartalige.i should of been given an MRI of both knees as the pain is in the same area of each knee.
Anyway my gp says it will be 1.5-2 years before I get the surgery because of the waiting lists.
In the mean time I work part-time doing heavy manual lifting which involves lifting and twisting my knees.i realise it not great for my knees.
If I stay on this job,my knees will be both a hell of a lot worse by the time I get the operation.
WHAT DOES ONE DO??????