2011 Macbook pro continues to have issues what should I do?

In 2011 I purchased an early 2011 2.2 i7 Macbook Pro new. Not long after I bought it I began to have graphics issues with the computer. The computer was sent into Apple and a logicboard replacement was done. I continued to have intermediate issues with the computer after I received it back. These issues became worse over time, eventually to the point of the computer not booting up. In addition to serious graphics issues and random shutdowns. This eventually led me to take my macbook on April 12th 2013 back Apple.

A repair was done in which the logicboard was replaced again. I received my Mac back on April 19th. Today April 22 my Mac shutdown again. Also some of the graphics issues from much earlier have come back. Some scrambled graphics and some tearing in apps appear on the screen. The computer shut down on me twice on two seperate occassions today. For no reason it just shut off. It use to do this before the logicboard replacement. I went ahead and submitted an error report to Apple after reboot.

I am a design professional and am associated with Appsterdam. The repair on my mac took a week and I feel far behind in my work. However just at the time that I am trying to catch up on my work. This Macbook pro has begun to go out on me again. I am so upset that I bought a unit from a bad batch or something. They have already replaced the logicboard twice as a result of these shutdowns and graphics issues.

I don't know what to do. Any information about what my next step should be would be greatly appreciated.