I agree with the other posters. I graduated with a low Biology GPA. My overall GPA was 3.48, but my Bio GPA was closer to a 3.1 (I even failed and retook a class). I got a job as a technician in an academic research lab for 2.5 years before applying. After a year of working I took two graduate level classes (for free). I went to every talk and seminar I possibly could, and spent most of my free time reading publications and taking some MOOCs. I worked really hard, but it paid off, especially when I was interviewing for programs. Because I went to a lot of seminars in various topics, I developed some knowledge of what types of questions researchers are interested in in various fields. When I ended up interviewing with someone in virology (my background is in cancer biology), I knew enough to hold a decent conversation for the hour interview. Basically, because I wasn't committed to a topic I found it easier to explore various fields.
I got into three top 50 programs, so I think it was the right decision! (I also was able to accrue some savings too!)
I would recommend checking out university job boards, and writing to the head of some research departments to inquire about openings. I actually found my job through Craigslist, but I don't think most PIs recruit that way.