Can anyone recommend me a good team for pic related in HGSS?

Currenty using Heracross, Typhlosion and Quagsire but I think I need a better team as I'm getting destroyed in the battle tower after the first 20 or so fights. I don't have the ability to trade or hack things in so any mons i use will have to be available in game.

Also Battle Frontier General I guess? Which teams did you use when you played through? Favourite facility? Do you prefer Emerald's or HG/SS/Plat's?