Since you have two amine moities, both can be alkylated (both the pyrazole-nitrogen and the amino-nitrogen) upon treatment with an alkyl halide. Maybe you should consider utilizing a protecting group (for the amine group) which will block it for alkylation in the next step.
Another alternative is to transform the amino function into some other group, then alkylate the pyrazole and then transform it back to an amine.
Are you physically doing it or is this a theoretical problem?