Time to replace swollen battery

Question

Explanation
I've recently started playing World of Warcraft which has pushed my macbook pro to the edge of dysfunction. Due to overheating and my inability to understand exactly what the problem was at the time, the battery appears to have started to swell. I first noticed the problem when after approximately 5-10 minutes of gameplay it would reach temperatures of roughly 85C and then at about 40 minutes the MBP's screen would lock up for a second, then go blank and the sound would die off. The fan would still be running at the 6000rpm mark I have set on smcfancontrol and I would have to hold the power button until it shut off. If i leave it alone the fans continue to run, but it stays at relatively the same temperature. I have to allow it to cool down first before it'll turn on again. When it turns back on, the battery charge is completely depleted, which leads me to believe that the overheating is damaging the battery and making it lose it's charge. What puzzles me is that it still shuts off even when it's plugged into the wall. The battery is starting to swell, I removed it and set it on a flat surface and it teetered around until i pressed on it and it flattened to where all four corners touched the surface.
Question:
I have an apple store in my city, and i'm considering taking it there to try to get the battery replaced. I was going to wait until summer when I don't have to deal with school without a working computer, but it's becoming a problem frequently plaguing my freetime. If i took in my macbook how long would it take to replace the battery? I would just plug it into the wall directly, but I need the battery for mobility.

Answer 1

I had this very problem today (though sadly I didn't know it while I was actually at the Apple store). I took my MBP in because I was having 2 problems: The first was that battery meter wasn't keeping up with how much charge the battery actually had, and the computer would just lose power without warning while the battery meter still showed about 50%. The second problem I had was with the trackpad, which had become difficult to click, and would frequently click at random without being touched.
Unfortunately, they weren't able to figure out the source of the trackpad problem at the store, as it worked just fine while I was there, so we both assumed there were crumbs or something inside it and I was planning to just go home and try hitting it with some canned air again. I had tried that once already, but the tech suggested that if you remove the battery you can blast some air in the back of the trackpad button, which might have more effect.
They also suggested I try recalibrating the battery and bring it back in if that didn't have any effect.
When I got back, I took the battery out so I could get at the back of the trackpad, and that's when I discovered that it had a distinct bulge. In fact the battery was the cause of both problems, the bulge was so pronounced that it was pushing on the back of the trackpad. I had already bought a spare battery while I was at the store, so I swapped the batteries out and my trackpad problem went away.
I called up AppleCare to see what kind of options I had, and they are sending me a replacement. I also called up the store, mainly because the tech and I had both been perplexed as to why the trackpad problem (which had been severe enough to make the machine completely unusable) had suddenly gone away, so I wanted to let him know what I had found in case he ran into it again (I think it worked in the store because it was turned off in my cold car for the trip over there, so it cooled enough to take the pressure off.) They did say that I could swap the battery out in store in and it would only take about 10 minutes, but since I had a spare now I wasn't in enough of a hurry to drive all the way back out there...