Now this is going to sound evil, but it's a rehash of my alts in gov't thread. If your faction has 2 members and will dissolve in 48 hours and you're up against the wall finding no replacements...
-Buy an alt., become a citizen and join the faction.
Now, whether you declare the avi as an alt is up to you. There are ethical pro and con positions. Remeber, this is SL not RL. There are no real people only Avatars. The line is blurry, but I can't legislate for "souls" (ie real humans) because some don't believe in them in SL, and in any case you can't detect/identify/put one in a bottle in SL.