Is this a good party composition Options

[Patrick_hindman]

Right now i am having doubts about my current party composition

Protag necromancer
Jaheira
heardalis (bard blade dude)
cleric of helm
cleric of lathander
keldorn

I have played through some of the beginning parts of the game and found it very tough, as i dont have a compotent tank (all my characters have 100 hitpoints of less) and have very bad physical damage potential since i dont have any single class warrior and they all have bad thaco. I am banking on the late game potential of this party but right now each battle with magic immune monsters and high level fighters with high regeneration has been tough (i cant even kill gracen) and heardalis has very crap small repetiore of spells, bad armour class and very low health and for a person that needs to get upclose its really bad (If he is concentrated on by any IA fighters he dies in seconds even with stoneskin) so i have doubts about keeping him. So i'm wondering whether its worth the trouble and does this party have good late game potential.