egads! you seem to be rather new. but i will save you some time. unless you have money somewere in the range of hundreds of dollars your not using, molding isn't really an option. while adam makes it look easy its actually really long expensive prosess (like anything in this hobby) i myself had thought i might make molds but on discovering the price just decided to scratch build everything.
P.S you won't get that much reation in just the helmet, i suggest you try getting a full suit first
sorry if i seem a little blunt, but i just want to make sure you understand everything.