that pioneer amp is WAY toooo little power.. period..
audioban subs can sound alright, but with a little forthought you could have done better for the money..
all that aside, we need to know what the subs recommended RMS power is.. i am guessing they are 500 a piece MAX, but that isnt what we need to know.. we need to know the RMS! also, are they single or dual voice coil? and what ohm are they..
without this information, your question is UNANSWERABLE.. PERIOD!
that being said, i am sure you can find a QUALITY amp that will power your subs for the price range you are looking to spend..
lets say they are single 4 ohm subs, and lets suppose they take 500watts RMS each.. then you need a amp that will output 1000 watts rms @ 2 ohm (2 - 4 ohm subs wire together to make 2 ohm)
i feel they are more likely 250 watts rms subs, normally subs that have a max rating listed will normally have a rms rate of about 50% of max.. so 250 watts rms each means you need a amp that will put out 500 watts at 2 ohm..
a good recommendation in either case would be a phoenix gold x600.1
the xenon series amps dont care what ohm load you hook up, and a x600.1 outputs 800+ watts rms.. 800 will be a little on the low side for subs that need 1000watts, but will still sound awesome. and if they are 250 each(500total), then the xenon wll have power to spare, just be sure to set the gain carefully so you dont blow them
hope this helped without offending