Hi lovergirl26 and welcome to MyCE. :flower:
You could burn the image to a dual layer disc but to get it to fit on a single layer disc you need software to compress the DVD.
Any one of a number of packages will do this for you.
Have a go with the trial versions of DVDFab or DVD neXt Copy and see how you get on.
If you want to go down the freeware route check out DVD Shrink.