Both stats are considerably lower than they could be. Pure power allows a neutral 'Cham to reach a stat of 438, you's falls very short. Your speed is a tad below. You need to rebreed for better attack IVs, because there are other pokes who really outmatch this one atm.
Lopunny is most certainly not a good alternative. Medicham is a sweeper, while lopunny is what can only be described as an annoyer- It p*sses a few pokes off but doesnt do any real damage at all. Besides, we dont even know the rest of your team- make an RMT in the S&M so we can help properly.