what is Colleges, grad programs, MCAT, GRE?

College is where you go for undergraduate studies in a certain concentration of a subject (examples of studies that you would major in, in a college are: anthropology, biology, chemistry, math, physics, english, linguistics...just google any college/university and search through “undergraduate programs”).

Graduate programs are an even more specific course of studies that you undergo after completing a bachelors degree at a college/university. 

MCAT is an exam taken for medical schools.

GRE is an exam taken for graduate schools.

Are you looking to find a way into medical school or graduate school? 

If you want to treat patients, you need a medical degree. That's 4 years of college (any major and the premed classes, high GPA, good MCAT scores), 4 years of med school, and 4 years of residency in oncology (you don't have to find a school with a good oncology program until after med school, not after high school). You get paid during residency, but not much. 

If you want to do research, you need a PhD. That's 4 years of college (bio or biochem major is good, high GPA, high GRE and subject GRE scores, research experience in your field) and 4-8 years of grad school for the masters and PhD (it's not a set length program; there are courses, qualifying exams, and 1-2 theses/dissertations including original research in the field). Getting a PhD takes long in school on average, but it's cheaper - science grad programs pay YOU to get your PhD, so you graduate with much less in loans than a doctor. However, you'd also make much less money with a PhD than an MD. 

Either way, you should start at the best college you can get into. With a 3.3, that's not a fantastic school, but maybe a good state school or not-top liberal arts college.