Probably there is no need for you to upgrade to a more powerful GPU...
It will just add cost and power consumption for no reason.
Unless that is, Adobe or w/e dev that makes the software you are using, comes up with OpenCL/CUDA accelerated filters / routines that seriously outpaces your CPU using the GPU for the same task, in which case you would shop specifically for a card that performs well in this kind of compute (nothing to do with graphics really).
It will just add cost and power consumption for no reason.
Unless that is, Adobe or w/e dev that makes the software you are using, comes up with OpenCL/CUDA accelerated filters / routines that seriously outpaces your CPU using the GPU for the same task, in which case you would shop specifically for a card that performs well in this kind of compute (nothing to do with graphics really).