I often see questions of the type "I want to study X but my school only offers Y" posted in these forums. I can understand that there are pressures to go to a certain school - scholarships, close to home, family expectations, etc. But it's important to take some time to really question why you are at the school you've chosen if they don't offer the program you want and consider changing schools if another program the aligns better with your long-term goals is offered elsewhere.
That said, of the biomedical engineers that I know, most came through electrical streams in their undergraduate studies. None had a second major as biology. That's not to say that learning biology would be a hindrance. I think it would help immensely. But from what I've observed the BMEs tend to pick up the biology they need in courses designed specifically for them.