Help! connection to kitchen faucet hose/pipe leaking

[pineapple808]

Attempting to fix a leak under the sink. See pic below. From what I can see, the leak is happening where the circled part connects to the hose that leads to the faucet. It is stuck in place. Doesn't seem to want to loosen or tighten. But leaks like mad.

http://www.flickr.com/photos/zizi808/7810274744/

Questions:
1. How to fix?
2. What types of tools/parts need to be bought/replaced?
3. Is this something I can do on my own or should I call a plumber?

Thank you in advance.

 

[IFIXH20]

Pineapple, most leaks that shows up there is coming from up higher and running down the supply line, not to say that it isn't leaking from there, Take a flash light and look under sink where the faucet sets to see if the leak is higher.

 

[pineapple808]

Thanks, but water is now spraying horizontally, not from top to bottom, so I'm pretty sure that it's what's happening here.not leaking from a higher source. Also the hose that connects from faucet is dry

 

[IFIXH20]

First thing first, does the shutoff valve works

 

[IFIXH20]

Take a measurement of the supply line , go to your local big box store to pick up a flex faucet supply line. You will need pliers and/or a basin wrench. Make sure the shutoff is in working order.