1. your battery probably needs to be conditioned. make sure you are taking it all the way down to 1%, and charging it all the way back up before you remove it from the charger (whenever possible). this is how you get the best life out of it. to be losing percentages at this point is a bit unreal; my 4 year old powerbook still goes to 99 or 100, and has only lost about 5 mins of real-time battery usage over the years. Then again, i've always used the aforementioned method.
2. the whirring noise is probably nothing to worry about, especially if it's very high pitched and only audible when you have your ear on the grill. contrary to popular belief, computers do in fact make noise! as long as its not a grinding or hissing, and your machine is running fine you're probably okay.