First - obviously I don't know you and anything about your application. So this is just my opinion in general.
I honestly think it wouldn't help as much as the cost would hurt. Really. I know a lot of people do the MA thing first to make themselves a better PhD program candidate. But the cost is too much, IMO. Is this your first time applying to PhD programs?
If this is your first round of applications, I would say to wait a year. Try to gain more research experience as an RA or lab manager and build connections. Then apply next round again, and include masters programs again. Go from there.
Some PhD advisors like if you already have your masters - they don't have to teach you as much theory and can focus more on research. Some dislike it when applicants already have their masters - they think you're already trained in thinking in a certain way and will be less flexible. Personally, I think it's better if you can go straight to PhD. Just my opinion.