Crankshaft Sprocket replacement trouble

I'm definitely no mechanic, and I'm having trouble replacing the crankshaft sprocket on my 1994 Pontiac Sunbird. I've gotten the front timebelt cover, timebelt, camshaft sprocket, and timebelt tensioner off, but the bolt holding the crankshaft sprocket on does not want to budge. I need to remove the crankshaft sprocket because it needs to be replaced (some damage to the teeth) and I also need to replace the water pump, which is behind the rear timebelt cover.

I've been doing some searching, and it appears that some tools may help, but
I'm not sure. A harmonic balancer puller seems like it would help, but given what I was told a harmonic balancer is and what it does, I don't see how that particular tool will help me.

Any help would be greatly appreciated -- I can't afford to take the vehicle to a garage (I was given a quote of over $500 to replace the belts, upper radiator hose, thermostat, and water pump and over $350 just to replace the water pump) and the work has gone pretty smoothly up until this point.

Thanks to all who are willing to help me!

I'm not sure which direction that engine rotates, but if it's clockwise, you can wedge a breaker bar between the chassis (or ground) and bump the starter a couple times; works everytime for me. Another option is to run some rope down into a cylinder and use that to hold the crank still while you try and bust it loose.

I'm sure others have more suggestions.

i know this sounds wierd, and the first time i used it it actually worked, (much to my surprise) i'd try the rope trick or the breaker bar starter trick first, but if all else fails you can try this.

if you have an impact gun, you'll need it for this step. if no impact gun available, use the rope trick and turn the crank as far counter clockwise as you can, then use a torch to heat the head of the bolt till it's cherry red. ONLY the head of the bolt should be flamed, don't put the flame anywhere else or you could melt the balancer. just move the flame in a slow circular motion until the entirety of the visible portion of the bolt is cherry red and then break it loose with your breaker bar. you should be able to spin it out easily at that point. toss the bolt in a bucket of water. you may wish to buy a new bolt, but it shouldn't be any trouble to reuse the old one.

i last did this on a 94 isuzu oasis (accord 2.2l engine)