Need help understanding burning Dual Layer

Can someone please offer a tutorial or some guidance on burning dual layer dics?

Problem: I have an iso just over 7gb and all my DVD+R discs have a max of 4.7 gb. The writer states, " RW DVD +R DL" so I am assuming I can burn dual layer. Does that mean i need a dual layer disc? Or can I use the DVD+R 4.7gb disks? Also, is there a freeware available for buring the iso image?

I've never ran into such a simple problem and been so confused. Any guidance/advice would be greatly apreciated.

Cheers

Yes, you'll need a dual layer disk to burn over 4.7GB of data

Check out ImgBurn for burning ISOs and more:
The Official ImgBurn Website

Check out Doom9 for burning help:
Doom9.net - The Definitive DVD Backup Resource