After getting the Service Battery message, I took my MBP into the Apple Store to get it diagnosed. They said the battery needed to be replaced, I've searched all over for battery replacements, but the prices are all over. Anyone have any suggestions where I should purchase the battery from? I am using a mid 2010 MBP 13.3 in. Also are the batteries for the 13 and 15 in the same? Thank you!