Carb Question

I brewed an Imperial Pumpkin Ale for a party this weekend (sept 22nd), i let it go for 4 weeks in the primary, then bottled on 8/26, so its been almost 4 weeks and the carb level sucks. A tiny hiss when i open it, no head at all, even when i let part of it dump in which would make an ordinary beer fizz over, and not very noticeable on the tongue.
I sampled one 2 weeks in, 3 weeks in and tonite(26 days), and this past one seemed to be a tad bit better than the previous 2. it did have some of the bubbles rising from the bottom of the glass. but like i said above, barely noticeable.
obviously it wont be ready for this weekend, but my buddy is having a party on Oct 13th (3 weeks away for a total of 7 weeks in the bottle), SOO my question - should i just wait it out, or crack the bottles open and ad a pinch of s-05 to each bottle.
if it were anything but a pumpkin beer, id just throw it in the basement for a while and forget about it. but since it is, and tis the season, me want pumpkin!!!
i also have some carb tabs. but im thinking the yeast is stressed due to not making a starter and just using 1 packet in a 9.5% beer.

What temperature have you been keeping the bottles? If it's 9.5% abv it might take a couple months to carb up anyway, if you've been keeping it below 70 degrees it can take even longer. If you're sure you added the proper amount of priming sugar, I'd just wait it out and not mess with them.

The word "Imperial" should be a clue....I've had big beers take anywhere from 8 weeks to 6 months to need to carb up. So I'm not surprised one bit that it's not carbed at 4 weeks.

You don't need to add more sugar to the beer.....the problem is not lack of sugar, it's lack of energy on behalf of the yeast to EAT the sugar you already put in there. If you were to add more, that would mean that eventually when all the sugar is consumed, you would have bottle bombs....

thanks, it was hovering in the mid 70s during the early part of bottling. now that its cooling off, its probably around 68-72 in my basement. i guess the extra aging will help out some of the flavors mellow, the vanilla kick is a little strong but no hot alcohol flavors. hopefully ready in october/nov, otherwise if its one of those 6 monthers, i guess i brewed my 2013 pumpkin ale early

tried another tonite. its 40 days from bottling and slowly coming along, but still pretty flat...the vanilla kick still strong, and the alcohol hotness was present more this time. BUT the aroma was quite nice...i think itll eventually become a good pumpkin beer. at this point ill be pretty happy if its ready by thanksgiving.