1 - Change the stock Condensor to Multi Flow or Multi Aisle condensor of sanden that comes in new cars now a days, That will improve cooling by atleast 20 to 25% for sure, And over all load on cooling system and car will decrease this is tested
The gas leakage problems will be solved as well because with Multi flow the pressure inside the system will not increase too much to develop leaks.
2 - Get whole system serviced,
3 - Install good quality Fan infront of condensor get corolla 88 FAN.
4 - Use R12 Gas cools better than 134.
If u want i can refer you to my mechanic he will do all this and car cooling will be geat but kharcha hoga