you can get batteries from ebay. 2450mAh battery for about 6usd.
it works better than stock (ofcourse not as "real" 2450mAh but still better than stock 1350mAh and what do you expect for 6usd)
ordered 1700mAh from ebay (kinda same 6usd) used it for a year and it still works. just wanted bigger (it is a bit better but not much) 6usd is not that much for a battery since the stock/original costs around 30usd. this 2450mAh one i currently use has been working flawlessly for about 4 months now and it has not died (during snowboarding, days in cold, after full mountain day(locked in 2G mode) with gps/sports tracker 60+% was left) etc. since that stuff comes from china you can always get a "real bad" one (as described in the link-post #2)