Hi gelato, welcome! I am new to this forum myself, and lemme tell u what I know.
GPA is indeed a huge factor, I guess you would have to choose the school wisely because some of them are rather slightly more demanding. HOwever, it doesn't stop you from applying if you can KILL the OAT. (Well, in fact, that is my purpose right now...study hard, show some determination..work hard.. excel at the OAT). But you should still apply, you never know what happens... the future is in their hands once you give in your application form. ON top of that, you have your personal statement, and all other factors that can give you a boost to your application.
Then, I guess that rektaing some courses would also help because you can show to the admission comittee that you can definitely improve your grades. A master program might give you an edge to applications (i.e. Waterloo in ON, Canada), but I am not sure if you can really benefit from this. Say, some schools will focus on the marks of your prerequisites... I am working out on my marks by showing them that I can take advance level (graduate) classes. I hope this game plan would work out fine for me.
There are different ways to go forth to apply. I am going to apply also next year. So this year, I am completing some prerequisites, as well as studying and writing my OAT (before the end of this year...) and keeping up with some volunteering work and shadowing.... Plus I have a laboratory work contract going on, and yea... despite all this, my prerequisites marks are a bit ****ty...but my overall GPA is good enough to give it a try.
Let's keep in touch, we might bumped into each other by next year!