I really enjoy Biology and I would like to continue pursuing a degree in it, but will this hinder me for law school acceptance?
No, a degree in biology will not hurt in you when it comes to law school acceptance. If anything, it may help you stand out from the sea of English/Poly Sci/Business majors. Law schools don't seem to care much about your undergrad major. I suppose a degree like Dance or Landscape Architecture might not be considered especially good preparation, because there is very little reading, writing, and logical argumentation involved. Even then it might not matter much.
Should I switch majors to get a higher GPA? Any help would be appreciated!
This is a somewhat different question, because law schools do care about your GPA. I can't tell you what you should major in, but whatever you decide you've got to get high grades. Your GPA and LSAT will almost entirely determine your law school options. It is very much a numbers game, and they care more about the actual numbers than they do about specific majors, grade trends, major vs. overall GPA, etc. People worry about these things, but in most cases they make very little difference.
Personally, I wouldn't drop something I loved just to boost my GPA. It's difficult to divine the future, and you may end up doing worse than you think. The upper division humanities seminars you'll take in your junior and senior year are considerable more demanding than the intro lecture courses. I think most people do better when they study something they like. Just my two cents.