If you still want to bring your old MBP back to life, I just replaced the battery on my sister's 2011 MBP with an aftermarket one from Amazon. There were a lot

If you still want to bring your old MBP back to life, I just replaced the battery on my sister's 2011 MBP with an aftermarket one from Amazon. There were a lot of pro/con reviews and it's only a couple weeks in but so far it's great. I went the one branded by Anker and it came with the correct screwdriver which was a nice touch. Installation was very simple. She also needed a new HDD so I put in an SSD and the machine is surprisingly zippy with the latest OS X.