First of all get your car's heat sensors checked. I don't think needle should remain at normal position if radiator is spilling water. Secondly, get the radiator cleaned thoroughly & check fan speed as well as mentioned by "scorpion80". You may need to install a relay if fan speed is slow.
After cleaning the radiator, carefully watch that the mechanic is properly connecting the pipes & no pipe is un-duely pressed from somewhere... Mechanics often do such blunders to get rid of the task...
I am sure these steps will either solve the problem or you will atleast identify the point of failure.