what might be wrong with my 73 super beetle

so i just got a bug a little while ago but it had a rusty gas tank. it was running
but i parked it till i could get the money to fix it. i recently fixed that but wasnt
getting any spark. so i went ahead and replaced that everything to do with
that too. plugs wires coil and distributer cap. oh i replaced the carb with the
tank too.
i got it running. i had to jump it off the battery was week. so while it was
running i sweetend the sounds by twisting my distrubuter a bit and tweekin
the gas flow and idle and it was sounding SO SWEET! Man i was so exicted!
i let it run for a while still plugged in to another cars battery. i put maybe 4
gallons of gas in it.(previously i had been direct out of a fuel can.)
disconnected the cables and cranked it back up, it worked! let it run for a bit
then jumped in and put it in first. didnt quite give it enough gas and stalled it,
the battery was still to week, oh the battery is probably a year old? i jumped it
off it fired right up with a strong battery, i let it charge for a few more minutes
and tried again, OFF i went. I made it about 3 miles! alright! i didnt get to
terrably far so it coulda been worse. so when it died, i was going about 50
mph and i just lost acceleration completely, then it stalled, i was still moving
so i tried popping the clutch, it fired back up but no excelleration even if i
mash the gas drifted to a stop and i couldnt get it to crank, someone helped
me try to jump it off, it woulndt, he ended up dragging me back to the house.
thank goodness for the kindness of neighbors