Toyota Repair: oil Leak, toyota camry, oil leaks

Question
Hi, i'm 90% sure of having an oil leak originating from behind the covers of the timing belt of my Toyota Camry 1996DX. Some few drops may be seen dripping on the ground after the engine has been running for awhile and then parked. The timing belt has been change at 123000miles and now the mileage is about 137944.Can you please advice what the problem could be and how much this is going to cost me. Thanks in anticipation for any advice.
NB. I took this to a mechanic and he told me the whole timing set needs to be replaced after i pointed out the problem. As a student with a tight  budget, i don't have enough money to throw away on unneccessary works. I just want to pay for the correction and nothing else.
By the way, does the toyota shop have a computer that they can hook up to the engine to tell straight away what the problem is?


Answer
The diagnostic computer is only useful to find electronic problems with the engine, it can't find oil leaks.
The most likely cause for the leak is either the camshaft seal or the front crankshaft oil seal, these should have been replaced at the time the timing belt was replaced so you would not now have to have everything taken apart again to replace these oil seals