You should have a manual crank for both the hitch and the slide. Takes a bit of work but gets the job done. Personally, I would just wait for the battery to get charged back up since you are plugged in.
I know you said you needed to hitch up but the hitch jack runs just off of the battery and is not connected to the charger except through the battery. If you need to get going immediately, then the crank is probably your only option unless you can find a neighbor to hook his car battery to yours so as to jump your tongue jack.
Barney