OK, at this point you have a carboy full of wine and it has been stabilized and had clearing agent added to it; it is in the process of clearing.
You have 1 liter of wine from the racking just after secondary and it probably has NOT had kmeta and sorbate added to it (it has not been stabilized.). If this is true, I'd just discard it.
If kmeta and sorbate has been added to the 1L:
After the bottle has set long enough to clear on its own, it can be utilized to top up another batch of wine. Maybe in a couple of months but not any sooner.
You can put 750 ml of it in a wine bottle with a bung and airlock on top. You can use a bung like this:
http://www.finevinewines.com/ProdDetA.asp?PartNumber=5148
Just turn the bung upside down and slip it over the top of the wine bottle.
On your full carboy of wine, after clearing is done and you rack, you will need to top up again with more wine.
BUT, you wouldn't want to top up cleared wine from a bottle of unstabilized or uncleared wine. The wine bottle will not have time to clear before the carboy has cleared and is ready to rack.
In a few months, the bottle will clear on its own. It will develop sediment in the bottom of the bottle, just like the carboy will, but at a much slower pace, since the wine bottle had no clearing agent in it. After the wine bottle has cleared, if you end up racking your full carboy of wine a second time, you can top up with the wine bottle.