You could get carb tabs from your local HB store and uncap, drop tabs, and recap with brand new caps. That would work just fine. I've done it myself with no problems. Granted I haven't done this with 7 month old beer though. How old were the caps you used and did you use pop top bottles or twist off bottles. What temp did were they sitting at when they were priming. I'd still try the carb tab thing but only do it on like six bottles and give 3 weeks at 70 degrees. If it works then do the rest. If not save the tabs til a later date. It should work though. I was watching a special the other night where they were talking about getting bottles that had sunk years ago and harvesting viable yeast from them. Give the bottles a shake after re-capping them to rouse the yeast.
Cry 'Havoc,' and let slip the dogs of war;
That this foul deed shall smell above the earth
With carrion men, groaning for burial.
Prim 1: Ogre's Inverted Extra Red Ale
Prim 2: Ogre's Hair of the Dog Imperial Amber Ale
Prim 3: Ogre's Relaxed APA
Sec 1: Honey Blonde Ale with Hefe Yeast
Sec 2: Scotch Wee Heavy
Sec 3: Ogre's Simple Mead
Keg 1: Ogre's Brown Ale
Keg 2: Ogre's Extra Red Ale