Most DVD drives can write to DVD+R DL
Download ImgBurn: http://download.cnet.com/ImgBurn/3000-2646_4-10847481.html
It can do both read the old disk and put it on new DVD media. It can also tell the user if the drive in use is capable of writing to the chosen media. With the limited info given in the original post, it is hard to give more useful info. Let's start with that and come back with more info about what has been done, with what software, and the hardware being used.
"I tried to burn it onto a +R dual layer disc but the software would not allow it." why not?