Since you mentioned medicare, I'll assume you are both in the USA. As you know there is the Affordable Care Act (Obamacare). Call your state group to get info on that coverage. The rates vary according to income and with such major procedures you face now, no matter what the premium is, you must try to get insured that way. That said, I have no idea if providers limit the number of patients they accept with these policies.

Call your county health department. Depending on where you live, there are varying kinds of safety net health programs. You may qualify and get basic service (cancer treatment would be covered) locally. You are getting much choice but you do get care.

A few weeks waiting while getting doctors and boards to review your case is not unusual. A month is pretty normal from time of initial diagnosis until a treatment plan is defined and started.