If the mpeg2 files have been made in dvd-compliant format, then you won’t have to convert the video, only author it to dvd-video.
The specifications for dvd-video vary according to where you live, and the standards used in your country. For example, the US uses NTSC. Europe, and most of the rest of the world use PAL. Normal specifications for NTSC would be 720 x 480 resolution, 29.97fps, 48khz audio in ac3, pcm or mp2. PAL would be 720 x 576, 25fp. though there are other acceptable specifications as shown by this page at wikipedia: http://en.wikipedia.org/wiki/Dvd_video
So, armed with that info, you can look at your mpeg file and check the specs with MediaInfo. (free to download and use). http://mediainfo.sourceforge.net/en Be aware that many people trip up on the audio specifications, using 44khz audio found in most other formats (like cds) rather than the 48khz necessary for dvd video.
If everything checks out, you can import to a dvd authoring program like DVDStyler or DVDAuthorGUI and make your dvd, then burn to disk with Nero or ImgBurn, or any burning program capable of burning dvd-video.
If you have to reencode, you can use DVDFlick, AVStoDVD or FAVC to make your video compliant, build a menu and output to a finished dvd ready to burn.