You see I really want a Garchomp - but the only problem is, is that I want a Garchomp with jolly in B2; So is there another way of getting a Garchomp with jolly or do you have to get through black tower to get it. My other question is that if you can't get Garchomp with jolly (you probably will but I'm sure it will take a long time) then is there another way of getting a speed like jolly (e.g using proteins, increasing speed in join avenue) ?
Well you cannot get any other Gible/Gabite/Garchomp in Black 2 except the Gible from the Black Tower. But you can take that Gible and breed it until you get a Jolly Gible. Or you can just Soft Reset that Gible till you get one that is Jolly. You can also transfer one from D/P/Plt. Or your last choice is to breed the Jolly nature off another Pokemon in the same egg group as Gible(Dragon, Monster) onto a Gible.