your upstream is fine except the cartridge, upgrade the speakers. i can't recommend any monitors in your budget because i only have exp with floorstanders. however, i'd want to try silverline sr-17 or totem mani-2 in your situation.
if you must get a new tt, i've heard good things about linn lp12.
if you must get a new tt, i've heard good things about linn lp12.