This set up for your budget is pretty good.
But here is another set up possibility
Helm: Serpentine Helm *immunity to venom*
Ammy: Occult (Anguish or Fury Switch)
Body: Ahrims (Karil's Leathertop)
Cape: Mage Arena Cape (Ava switch)
Legs: Ahrims (Kari's leatherskirt)
Shield:Malediction ward or book of darkness
Boots: Eternal or Infinity
Gloves: Barrows
Also take a look at the best in slot page for osrs
http://2007.runescape.wikia.com/wiki/Armour/Highest_bonuses