How about repairing the existing wiring (if it's that that's the problem) and seeing if you're happy with it before you go spending money on new pickups? Am speaking from experience, I had all these plans to mod a Precision I bought recently, but found after playing it for a few days that it was perfect as standard.
If you're set on Quarter Pounders, they tend to be mid-scooped (there's a tone chart
here, scroll down a bit for the bass pickups). Usually Quarter Pounders are bought by the punk rock/metal crowd (including myself). If you wanted something more all-round, maybe the SJB-1 or SJB-2? There's plenty more suggestions for J pickups if you do a search.