I would recommend ConvertXtoDVD, but since you want to use free tools, you could try FAVC, since it is supposed to have support for .wmv files.
Or you could use WinFF or SUPER to convert to dvd compliant mpeg2 files and put them into dvd format with a free authoring tool like DVDStyler or GUIforDVDAuthor. Make certain that when you convert you have both the video and audio in compliance with dvd specifications before trying to author to dvd format.
FAVC comes with ImgBurn, which is a highly recommended program for making and burning ISO’s, and more. You might want to look at the latest version which is free to download and use…and look through the guides at the ImgBurn forum.
To back up a commercial dvd, download DVDFab HD Decrypter (free) at http://www.dvdfab.com/free.htm
Rip to the hard drive, then use DVDShrink (also free) found here: www.mrbass.org Read the guides on using Shrink. Most commercial dvds have to be compressed, or have extras removed in order to fit onto a single layer blank dvdr. And that is what Shrink will do for you. You can set Shrink to output as an ISO and then you burn with ImgBurn.
Another, slightly higher quality option is to use DVDRebuilder to reduce the size of the movie. Much slower, and the free version of Rebuilder lacks some options on what you can remove from the movie. If you want to remove extras, menus, etc., it is best to rip just the movie only with DVDFab HD Decrypter, then use Rebuilder. This applies to the free version only. The Pro version has many options.
Use Rebuilder on large dvds that need a great deal of compression, as it will give better results on these types of dvds than a transcoder like DVDShrink.