What are my chances of getting into graduate school for biochem/biomedical science.?

What are my chances of getting into George Washington University, or any graduate school for that matter. I want to major in biochemistry with a concentration in metabolism. Right now my lack of physical chemistry is preventing me from applying to most programs, and the schools offering it in my state are either much too far for 3 day a week travel or much too expensive (that one course is more than a whole semester at my school!) I spent most of my undergraduate career paying out of pocket (close to $40,000 room and board) before i received a full scholarship, so i am not looking forward to paying more than $3000+ for one cl when tuition alone at my school for 18 credits wasn't even that much. GW doesnt require pchem for the phd program. I have decided that getting a masters first is not a bad idea. I have a 3.5 GPA, graduated c u m laude. I have a year of biochemistry experience, and 6 months of unrelated research experience. Will get great recommendations from my research mentor/biochem/immunology teacher, physics, and seminar professors. I have yet to take the GRE, but my preliminary scores show 600 math and 510 verbal, which I know is on the low side but i am studying hard to get the math score up. I am taking a year off before grad school. What can I do to improve my chances? BTW, I am also applying to howard. I was also thinking of the georgetown masters program that does not require the GRE, but think my GPA may be too low for that program. What would be a good safety school for me?