The TYPE of processor, AMD or Intel, makes little difference, in fact, none, in which card to go with. One has nothing to do with the other aside from Intel processors being better performers in most cases.
For 150 dollars, there are no other choices aside from the R7 370 or GTX 750 TI. Your PSU model is going to factor in here as well since it needs to both be capable enough and have the proper connectors depending on the card model's requirements.
With an R7 240 currently, either of those cards is going to be a significant improvement.