1. Why were you studying Biomolecular science if your goal was to become an NP? I suspect you were a pre-med, realize you can't get into medical school with that low of a GPA, so you are doing NP as a "backup." If that is the case, please be aware that the odds are stacked against you. Admissions committees at nursing schools aren't going to be pleased that you see their career as backup, and you will need to write a really good personal statement that explains why nursing is your passion. You need to research the profession and prove you aren't just falling back on it.
2. Speaking of researching the profession, please note that there is no such thing as a "Labor and Delivery Nurse Practitioner". I actually believe if your goal is labor and delivery, a Nurse Midwife is more relevant. A women's health NP is more trained to the role of an office based gynecologist, acting as a female specific primary health care provider.
3. Direct entry MSN programs are the most competitive of all nursing programs
, thanks to the numerous "Best job" articles showing the smiling nurse practitioner with dollar signs around her head. Most programs get 500-800 applications for sometimes as few as 50 seats. a 2.57 GPA will not get you into ANY program. If you can get it up to above a 3.0, you have a shot, but even then it will be tough. As others have stated, most people accepted to direct entry programs have a 3.7+ GPA. You are taking 7 years worth of courses (typically 4 year BSN and 2-3 master's degree) in approximately 3 years. You have to prove you can handle that.
I suggest you really do some more research before you commit to this. One thing I always ask the hopeful direct-entry MSN students is this: Do you want to be an RN first? I know so many pre-meds who didn't quite get the grades they needed for medical school tried to do an MSN as a "backup." Many couldn't even complete the BSN portion because they had no idea what being a nurse entailed. They thought it would be as simple as passing out a few pills for a bit then moving right onto the NP program, but it's just not that easy. Nursing school clinicals involve a lot of hands on patient care that is not for the squeamish - debriding wounds, changing linens covered in blood and excrement, inserting enemas, giving bed baths, cleaning up code browns, etc etc. On top of that there is the stress of knowing you are the first line of defense if your patient crashes. If you can handle that, get your GPA up to at least a 3.2 or higher, and really learn about the career, then go for it. If you don't think you can handle the RN part, go for PA school. It's honestly no more competitive than direct entry MSN programs are these days.