8,1 macbook pro battery life

I am completely defeated in diagnosing the problem with this macbook pro. I ordered a NuPower 65 watt-hr battery this past summer. The battery life since has completely tanked--1 hour of running pages and iMessage will drop it 60 percent. This confused me, so I checked all processes, and nothing was running the processor hard, the fans were not running high, and the computer was about normal temperature. I have reset the SMC and PRAM multiple times, and calibrated the battery as indicated with NuPower's directions. Still, no change.

Further, I have noticed that the computer will run under these similar conditions (pages, iMessage, normal safari--no videos) on 5 percent for about an hour. Which lead me to the SMC reset. But, with no change in battery life, the next week its at 5 percent, with the same work load, it dies immediately at 5 percent, and starts to indicate needing plugging in at 6 percent.

With the stock battery (from 2011, about 700 cycles) it was getting 6-8 hours of normal use, depending on Flash usage. Now, maybe 1.5 hours. The cycle count is at about 68, since I can no longer use this computer reliably, I only use it at home. I do not leave it plugged in unless it needs a charge. What can I do? Is the NuPower battery in need of warranty?

Thank you all!