External HD failure. Data recovery?

I have a 4 month old, 250 GB external USB hard drive that suddenly started clicking. It was totally fine before. I can still access the drive, but it’s very slow and several directories are missing or empty. A disc reading error message pops up if I try to copy anything off the drive onto my internal HD.

Is there any way I can salvage the data I want (around 80 GB) without sending it to a professional? Would freezing it work? Someone told me to mirror or make an image of the drive, but how would I do this (total newbie here). I don’t know where I would save the image … should I buy a DVD burner?

Please help!