since you are from chemistry area, biomedical engg will be very different area for you. I am not sure if you have taken a look at the courses of the biomed engg or not, but all the classes in the biomed engg (in undergrad) is totally a mathematical and engineering class and very few bio/chemistry classes. So, I think even if you get into the biomed engg grad program, you will have to take a many undergraduate level classes related to biomed engg as a prerequisite for graduate level classes.
talking about the admission, gpa is not the only things. 3-3.5 is fine. letter of recommendation, personal statement and other things are also important. what you have to think is there are few schools that has graduate program in the biomed engg. you have to find and apply carefully which one will be appropriate to apply. 
btw, if you get into the phd program, then mostly you will get full scholarship.
goodluck.