Ingrins

Hey all. So I am graduating from my Univeristy May 2015 with a GPA of 3.2 overall. I eventually want to get a PhD in Microbiology but know I cant do it right away. I have been in the military for the past 6 years and would like to go back after grad school. I guess I am just stuck as to what I should do next? Should I get some lab experience and take classes as a non-matriculating student or should I just take the GRE and go for it? THanks in advance and any and all advice would be greatly appreciated.