Hi, agrumpycow.
If you're not conversant with manual exposure compensation it can seem a little daunting at first, but it wll only take you a few minutes to get the hang of it, and will be one of your best tools for future use.
Have a look in your camera instruction manual.
I visited Panasonic's website, and the full instruction manual for the DMCFZ18 is downloadable in case you've lost it.
This is the url for the download: -
http://service.us.panasonic.com/OPERMANPDF/DMCFZ18.pdf
(Look on pages 45 & 46 of the pdf file for manual exposure compensation).
The method used on your camera is pretty much the standard for digital SLR types, and you can use it to force the camera to either underexpose or overexpose, dependant upon what you need at the time.
If your main subject comes out too dark - set the controls to overexpose (plus)
If your main subject comes out too light - set the controls to underexpose (minus)
The degree of plus or minus will be something of a best guess until you get used to this type of thing, but if you don't get it right first time, just add or reduce your plus/minus settings and give it another go.
Then just set the controls back to zero/default when you've got a pic that looks correct. (Don't forget, or you'll be permanently under/over exposing until you do reset).
If you're still struggling, post again. I'm sure we'll be able to sort you out one way or another.
Best of luck
Mike.