Thanks for the many good responses that I have received here.

I had used the wrong screw driver to tighten the nuts in the clamp.
The screw driver was just too small. Therefore, I could not apply
enough force to tighten the nuts. I bought a BIG screw driver and
tightened the nuts again. This time worked much better. But I still
see a tiny stream of water spraying out.

I will use the following advices that I have received here to fix the
last tiny stream of water:

1. First, I will warm up the hose end with a hair dryer to soften it
a little bit before I insert the brass tube. Leaving it in hot sun
should also work. But I am not expecting any sunny days until Friday
-- I will have to make do with a hair dryer.

2. Secondly, I will try tighten it one more time with _ALL_ my
strength.

3. If doing this still doesn't work, I will try the telfon tapes.

4. If the telfon tape still doesn't work, I will go back to Home
Depot to look for another way to re-connect the hose. May be I can use
a male connector and a female connector to get around with this
problem? I know Home Depot sell a male connector to repair broken
water hose end. I don't know if they sell a female connector though.

I will see how thing goes.

Jay Chan