My auto and quick save went out today on a steam copy of new vegas.
When I open the saves folder, the only ones there are:
autosave.fos.bak
autosave.fos.tmp
quicksave.fos.bak
quicksave.fos.tmp
the .tmp files are the correct ones, but when I delete the .bak off the other ones, they send me back to an earlier save.
Now, both files are empty. If anyone could either help me with this or give me an autosave mod, I'd appreciate it.

Check CASM ( http://newvegas.nexusmods.com/mods/36730 )

Unfortunately, your situation is not unusual. Both quicksave and autosave are known to be bugged in pretty much all Bethesda games since at least Morrowind so what happened to you happened to alot of players.

The .bak should send you to an earlier save since current autosaves/quicksaves are backed up then a new one is made.
The .tmp however indicates your saves aren't completing correctly. There should be no .tmp at the end of either the auto or quicksave.

THis could be a anti-virus issue or maybe folder permissions. Did this just start happening? CHeck your event viewer for errors or otehr issues.

BTW, never rely on just auto or quicksaves. ALways make an occasional manual save every 10-20 minutes or so.