to be honest, depending on your gear, you don't even need new pickups, I have a fender bullet strat myself, after owning an Abilene (no-name brand) guitar, and to be honest, there's no such thing as "i need to buy this to get this tone" I've always been able to at least manage.... plus if im recording to a computer the options are almost limitless.

I've heard seymour duncans are a good brand to get, as i had the same idea as you at first, but since getting a pod 2.0(borrowed from a friend), plus what I already know due to programs like audacity, its that if you really want to get a heavy tone, even on **** equipment, generally crank the bass and treble, drop the mid range, make sure your distortion pedal's distortion effect is on 10 and do the same with the bass and treble again, Hopefully this will do what you need and i havent just stated things youve already done,
Otherwise, there are cheaper alternatives to seymour duncans, hell ill even ring my local guitar store if you want and see what i can find out

I suppose it is a little different for me, my amp died so im using a computer.... .all the more reason i say its possible to get any tone you want!