1998 Toyota Camry Radiator replaced on Monday; still leakin

I had recently got a coolant flush on 2/7/08 and the next day I noticed steam coming from the car wihile sitting in the drive thru. I thought maybe it was because it was cold outside. The next day as I was backing out of the driveway the car turned off (while in reverse gear). I noticed a bright green spot in the driveway, so I checked under the hood and coolant was EVERYWHERE! The car never ran hot meanwhile. So I took the car back to the mechanic and they said it was the radiator and showed me the crack in it. So it ended up costing me about $400 to get it replaced. When I left the mechanics on Monday, I went to pick up my son and when I was coming out I noticed a green puddle. So I took it back to the mechanic and he said the coolant was coming from where the technician didnt clean it off properly. He pressure tested it and said everything was fine and cleaned off any excess. Today, I am still noticing very small puddles of coolant. Is this normal? Before the crack was discovered, I never saw coolant leaking before. What else could be the problem? I got a new water pump in 2004 as well as all my belts were changed. Please let me know what the problem could be (if any) so I can stop worrying and get on with my life. If there is a problem I want to get to the bottom of it while I have the money to fix it.