First off, do what Faldeney suggested and get CHA potions/buffs.
Second, if you are soloing, root/snare EVERYTHING, and make sure you have your 5mana nuke (Hand of Lava at this level) somewhere in your spell set - it might not be fast, but when running low on mana, you can still fall back to keeping the mob snared and 5mana nuke it to death.
Third, reserve a slot for your Rune (Steelskin) and try to get a mage summon you some Jaspers. You have no means to heal yourself, so the extra HP buffer from rune is handy if the mobs keep resisting root again.
Spellset I'd suggest for the solo Wizard on your level:
Harvest - yes it stuns you, but if the mana helps you killing your rooted mob, its worth it. Also helps cutting downtime a bit.
Immobilize - Rooted mobs can't chase you, and can be killed from the distance.
Bonds of Force - Root will break ever so often when nuking, and you can allways outrun a snared mob (or it gives you time to re-root it while it walks your way)
Steelskin - Your rune is a HP buffer in case the mobs made it to you and start beating on you. Requires jaspers/Summoned Jaspers to be cast, so best bug a mage to summon you some. Buying real jaspers might be too expensive, but if money isn't a concern, give it a thought.
Hand of Lava, Hand of Lightning - 5mana nukes for when you are oom but the mob still isnt dead. It's nothing impressive, damage-wise, but unless you have DF, you can allways cast this, and it's sure better then trying to melee a mob to death. 2 because mobs have different resists, and while one might work, the other might not.
Lightning Shock - Your biggest Nuke, to slay the beasts.
Gate - Sometimes the best option is to get out of the trouble as fast as possible, and that's what gate can do for you...