The thing with these martial arts is that you can't learn much in a short time. If you have an upcoming fight in a week then it's pretty useless whatever you learn in that short period. BJJ can be very good but it requires skill. Judo is somewhat better in your case because shoulder throws are not hard to master and it works well. Wrestling is good but I wouldn't do it against a bigger guy especially not during a street fight.

However, if there's no other way and you don't want to run away or use a gun then just use dirty moves. Poke the eyes, kick the nuts, spit, pinch and lie.