okay, here the answer to your situation.
buy the infiinity from
crutchfield,, 4 of them as instructed in my post(sell one) for $220 total
so that leaves you with that 2 ohm mono amp, so sell it here or on
ebay for some cash( I figure you get about $100) and then buy used directed 1100d or mono 1000 watt---1 ohm rated for about $150-180shipped price. could get lower if you go for the lanzar and other brands.
so you could be still spending under your budget,,, $220 +$80 for mono 1 ohm amp==300 depending on outcome of buy and sell amps.