Power brake booster leak

The 99 Buick Century I just bought has a vacuum leak in the brake booster. I heard a vacuum leak under the dash and upon checking where it was coming from, to my disappointment it is the booster. It is hissing through the boot where the rod goes through the firewall to the booster/master cylinder. Now, my questions are that this looks very hard to get at and looks like it could be an expensive part. Is it expensive and difficult to do? Is there a trick to accessing the bolts? They look impossible to get at under the hood. Also this is causing the car to die occasionaly. Any good source for parts or tech tips would be great help.

If you have antilock brakes, I suggest you take it to a mechanic or a dealer to have it replaced. Some of the newer boosters require special tools to replace.

Update: Bought a booster at a salvage yard for $35! Luckily I was there when it was taken from the parts car because the dismantler said it was very easy. It twists into place and is only held in place by a catch mechanism on the right hand side. Unhook the brake pedal from it, release the catch, unbolt the master cylinder and give it a counter clock wise twist and it comes right out. I had to remove the master cylinder for more room to get the booster out so the brakes had to be bled, but that was the hardest part. Thanks for the heads up GTP Dad (I did make an appointment with a mechanic to have this done) but this was one easy fix that I"m glad I attempted myself.

Thanks for the update!