So, you have a camcorder that captures to miniature DVDs?
Some events you have recorded onto 2 separate disks, and want to combine the two onto one disk - playable in a DVD player?
Firstly, you will need a DVD burner for your computer, and DVD capture/(editing)/authoring software. I use Sony Vegas and the Windows DVD Maker on Windows 7, but Vegas is expensive, and I don't know if Vista has DVD Maker.
As an alternative, you could try using Windows Movie Maker, but it is worse than useless for any editing.
You will need some way to get the data off of the DVDs. That's not my area of expertise, I mostly edit off of camcorder tapes. If you can hook your camera up to the computer by firewire, or copy the files off of the DVD using a DVD drive, that may be the easiest option.
If you need more help, just ask