Cut military spending by 90%, pocket 50% of it, and give the rest to NASA with a mandate to build an economical commercially viable shutlecraft and launch system that would permit daily launches and develop an orbital habitat capable of sustaining at least a quarter million civilians.
18.7 Billion for the entire agency? That's chump change. It's a joke. The military is getting around 711 Billion. Iraq and Afganistan alone are getting 170 Billion, and they're both substantially more hospitable than outer space is. They actually have atmospheres.
That idea is not likely to happen. Also, where are you getting these numbers?
NASA may scrap plans to return to the Moon
So much for a way station between Earth and Mars... Perhaps scientists can shorten an Earth-Mars trip by employing solar sails on the spacecraft? It ought to be more economical than using rockets.