What PhD programs (Business-Marketing) are open to older applicants?
As far as I know, there is no PhD program in the United States for which it is legal to discriminate based on age.  Nor is it just a matter of legality: at least in the circles I run in (I have done graduate admissions for the PhD program in my department at a state university) this is not just a technicality: holding a candidate's age against them would be viewed as grossly inappropriate behavior.  I have never seen even a hint of it.  My field -- mathematics -- is different from yours, but it is also one in which there is little a candidate could do in between their undergraduate and graduate degrees that would be viewed as clearly advantageous by the admissions committee.  From what I know, this is not true of the business community.  There are very few 22 year-olds enrolled in MBA programs; some prior real-world business experience is preferred, and there are prestigious "executive MBA programs" for older candidates who are already successful in the business world.  So I would guess that many applicants for a PhD in business/marketing are over 30.  Professionally speaking, what's the difference between 30 and 46?  Not much.  I honestly don't see why anyone would care.  

The bit about low GRE scores is a different matter.  You should check to see which GRE scores are taken seriously by admissions committees in your area.  Assuming that any of them are (a reasonable guess if they require them), I strongly recommend that you take the time to improve your scores substantially rather than try to look for programs that will take inferior students.  Remember that most US PhD programs take at least five years to complete.  It is really worth it to spend a year or two making sure you get into the best possible one.