Car repairs

My 2003 toyota corolla Sport check engine light keep coming on, I replaced the battery 3 weeks ago
and had to put water in the battery last night. I carried it to a mechanic and he said my catalytic converter is gone but he said I needed a major tune up, a water pump, belts replaced and transmission service at a cost of $595.00. In addition the catalytic converter would cost me $895.00 is this reasonableprices for these repairs. My cat was running good, starting up, no noises, just the check engine light keeps coming on and water evaporates from the battery.