How to calculate base resistor of a NPN transistor that drives a MOSFET?
The circuit won't work regardless of the value of R2. The MOSFET will remain partially on all the time (due to R1), and possibly burn up. Even if R1 was to ground, the emitter-follower would only give you 2.6V from a 3.3V output regardless of whether the supply is 5V or 12V.
You could do something like this (logic is inverted):



simulate this circuit &ndash; Schematic created using CircuitLab