Lvl 20 Mage, I hate this game (early levels frustrated me badly with mage, love this game <3 )
Congrats on reaching lvl 20! Please correct me if I'm wrong, but based on your build and gear, I'd guess you haven't completed The Ark of Lothasan quest yet. I think you will have a hard time there with that build. So I have some suggestions that are only my humble opinion:
I'd suggest specializing in either summoner + staff, or Spells + Mage Barrier + Wand (I will soon be posting a build & guide for this). It looks like you prefer staff and disintegrate, so focus on summoner in that case. You shouldn't need strength at all for Mage unless you want Body Builder or Massive Criticals advanced skills but imo that's not necessary either. A Mage build based on criticals might be interesting though (another style I've been toying with).
Heads up for the Ark, you will need Shock damage and with your build it doesn't seem like you have any (no Lightning, no Mage Barrier, no Sparkling). Without having at least one (preferably 2) of those things I'd be surprised if you make it very far through The Ark. Having Shock resistance will also help a lot and being able to summon at least a Sparkling will make things easier for you in with both shock damage and shock resistance.