How long does the battery last in actual use?
More than 1 hour? Depending on your needs, that may (or may not) be enough for now.
Unless you are searching for an actual Apple-sold (OEM) battery, then I would suggest that you look for batteries that have good reports from other users. iFixit sells batteries (or has links to other sites), and I think is generally a trustworthy site for repair parts. MacSales.com is another choice.
Or, you can wade through the listings on Amazon. I very often will look there (I purchase 5 to 10 batteries a year, as I do repairs for friends) again looking for lots of sales, with mostly good reports. So far, I have had good luck with replacement batteries. I have bought several with "NinjaBatt" brand. So far, good ones.
BUT, I also use the saying "Cheap laptop batteries are often not a bargain"
Good luck! There's a
lot of batteries on Amazon that are sold to fit your MacBookPro
Online shopping from a great selection at Electronics Store.
www.amazon.com