Bottling from a keg (no tap or CO2) question

So last September my brew club had a cluster brew which required required me to keg my beer so that it could be consumed and judged at a club party. To make a long story short, I now have about a 2.5 gallons of carbonated sweet stout in a keg with no way to tap it and no intention of purchasing a kegging setup. How would you go about bottling it?

I'm thinking I could probably just siphon it into a bottling bucket from the keg, but don't know about a few things, so here are my main questions:
1. When I transfer to the bottling bucket should I wait for it to go flat and then naturally carbonate using corn sugar or should I just bottle quickly while its still carbonated?
2. If I need to wait for it to go flat, how long should this take?
3. Again, assuming I will be carbonating it again, will I need to add some fresh yeast or will the yeast used to naturally carbonate back in November still be viable?

So it's carbed now and under pressure in the keg? Borrow someone's CO2 and picnic faucet setup so you can do the BMBF filler into a few bombers.

Read the sticky right above your post: "We don't need no stinking Beergun."

It's all you'll ever need to know about bottling from a keg.