What kind of trumpet mouthpiece would i need to play higher notes?

i have been playing the trumpet for 3 or 4 years on the same 7C mouthpiece and i can only play to an e or sometimes an F on the top of the scale, but its hard for me to do that. What kind of mouthpiece and size would i need to have a good size and be able to play higher?

What kind of trumpet mouthpiece would i need to play higher notes?
Practice is very important. I would try a Bach 5c though. This is a bigger mouthpiece and it will take time to adapt as well as more air.
Reply:i would get a 1 1/2c or a 3c mouthpiece
Reply:i dont exactly remember the the mouthpiece #, but get one that has a smaller inner cup and thicker border. that will help you play higher.