Level 1 of Mana Leech would help with the refill rate, and Mana Efficiency can drop your requirements.
Equipment bonuses should take care of the armour rating; if not use an enchantment or two to help if you start running into problems with magic damage or archers using stun arrows.
In D2:ED with my warrior I got my intelligence up to 20 and then stopped boosting it (except for a potion you find later in the game that gives a permanent +5 intelligence boost). I only put 3 points into Spirit.
In DKS playing a ranger on nightmare I have not put any stat points into intelligence or spirit, and have found between equipment bonuses / enchantments and Mana Efficiency that I have more than enough mana. Higher level armour in DKS has more enchantment slots than in D2:ED, though, so that helped. At the end of D2:ED I think all my armour had only 1 enchantment slot, most of which were Life Line; about half way through the D2:ED section of DKS armour pieces with 2 enchantment slots start showing up.
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