With presentations, and changes in direction it’s always good to come up with a plan, rather than just saying things aren’t the right way to go. Try and sell the business value for the different things that UX can add. So for instance, sales data and GA are good, but you really need to back them up with interviews or surveys etc because Google Analytics tell you the who, what, and how, but not the why. The why is very important and often forgotten.
My suggestion would be to present the process, and the different parts (UX mastery have a great example http://uxmastery.com/resources/process/) that can be accomplished in each phase. Give solid rationale behind why this adds value to the business and they will be more likely to jump on board. It could be that your boss doesn’t have a full understanding of UX, which is alright, you can be the advocate, help give direction and let them know that data driven design is awesome, but you still need to follow the other aspects of the process in order for that information to be useful!
Hope this helps, feel free to ask more questions