A little more power may actually make the plane easier to fly. The Prop change is a crap shoot if it will be an improvement towards making it easier. I would sudjest holding the plane at full throttle and feel which prop pulls harder. Also try not to jam the sticks when correcting the planes direction. Give it gentle/smooth inputs and give yourself plenty of room. Do not try to fly in a confined space. This will give you more time to react with smooth gentle inputs. Start with big lazy circles then change direction and always launch and land into the wind.

Good luck, have fun, don't quit!