I have a 2009 model. IT is telling me I have to replace my battery soon. How long would this take? I dont have a warranty, so can I just go to the Apple Store?
Yes, you can take it to Apple, but first check its health, rather than depend on IT to tell you if you need to replace it. Use iStat Pro (free) or iStat Menus ($16) to get accurate readings of your battery, temps, fan speeds and much more. Replacing the Battery in your MacBook (Models with built-in batteries) This should answer most, if not all, of your battery/charging questions: Apple Notebook Battery FAQ
It should be. I'd call ahead and make sure they have the replacement in stock. From the link I posted:
Apple usually has these things in stock. It should not take more than a day, but if they are very busy or out of stock on the battery it may take a few days.