Yes, except for the UI and controls, the PC and Xbox versions are the same. I played the Xbox versions of D2:ED and DKS (I have a computer now that can run Divinity 2, so am planning another playthrough on PC eventually).
Do you have Hide in Shadows, or a spare skill point to try it? It can also show up as a bonus on jewellery.
If your creature is active, maybe if you move back before summoning your demon you'll have a little more time that you can afford to stand still.
Another level or two would likely help. There are a couple things you could check before you reload, though.
Did you max out your enchantments, etc? Make sure you have level 9 Increased Damage and Increased Magical Damage on weapons (both if possible; the first a priority for a warrior/ranger, the second for a mage), Armour should (IMO) have level 9 Life Line and then Increased Mana, and for jewellery I went with Static Charge and then Magic Damage Aura.
If you have any malachite gems, you can add some level 10 Healing Auras on jewellery. There are a few malachite veins in FoV and you can randomly get malachite gems as quest rewards (any quest that lists random gems); reloading at veins and FoV quests, I ended the game with 65 malachite gems (which was a waste of time, really; next game I'll either use more healing auras or not reload).
Do you have enough gold to unlearn your skills, or enough free skill points to try other approaches?
If you've used a bow as a backup when you are low on mana, you could have the Bow of Orobas. A close range Splitting Arrow can do quite a bit of damage, especially combined with Way of the Ranger.
What kind of build are you playing (stats / skills)?
