Just got a machop and a machamp would be a good lategame thing for my team, problem is I use mgba and machamp is a trade evolution. What solutions are there?

As for my team I have other major issues I'm working to fix. I have like 2 steel types and 3 water types.

Its lombre, wingull, gardevoir, the first evolution of mudkip, magneton and Aron.

I'm considering a slugma or torkoal, and am contemplating building the machop. What would your recommendations be? I just beat gym 5 (barely, I need a team that isn't held together by my ace)