Have you ever played a caster on low levels? The casting abiliy isnt exactly awe-inspiring & more often than not you just melee things.
As Lorien says, put some points into UMD, start whipping those blur, stoneskin, resist & protect wands, cast from scrolls.... Heck, even just carry a stack of healing pots if all you care about is self recovery.
The more you play and learn this game, the more you will realise that self-sufficency is the best thing to strive for, once you learn that, you can do pretty much anything. Even the raging barbarian learns when to nickle & dime powerful mobs
As for Melee's soloing high level quests? MrCow & Shade have documented melee toons soloing quests
(sorry, its very late here & i cant find the links for you)
Anything is possible. You just have to figure out how.