Most people have added some very sound advise but a few points I really wanted to bring up again...
I would recommend NOT topping off your boiled wort with water from a garden hose. You pretty much are negating your boiling process. You want evertying from the boil on that comes in contact with your wort to be sterile. You should have an appropriate size boil kettle with the appropriate amount of water in before hand that will result in the boil bringing you down to the correct 5-5.5 gallon batch size. If you do not want to "build" or buy a chiller, as stated above ice baths work well, but you need to do this in a plastic container.
Please do not pour into a glass carboy for your own safety. I typically put my wort chiller in the boil kettle for the last 10 mins of the boil to sterilize it (this is after I have already cleaned it from the last brew.) From there I just hook the hose up and let it run for 10 -15 mins. That usually gets the temps down to a very reasonable range. Then pour into your plastic fermenter, or glass, if that is all you have. Just do not pour boiled water into a carboy.