OK, the first thing I have to say is...don't go to law school. Seriously, don't. The market is saturated with lawyers and there just aren't enough available jobs for lawyers right now. Additionally, the business model for law is completely out of step with the current economy. Yes, paying $100K+ for a law degree made sense when the average starting salary was in the low six figures but now, that number has dropped dramatically. Abovethelaw.com ran some great articles over the past 2 years that shows just how much the math doesn't work out anymore.
So, are you still sure you want to be a lawyer? Is it the only thing you can see yourself doing? Is it why you went to college in the first place, so you could eventually go to law school and become a lawyer? Do you want to be a lawyer so you can help people? If the answer to all those questions is yes, then OK, you should definitely pursue law school.
You're going to have to go to a Top 50 school if you want to find a job after graduating. I know it sounds elitist but it's much better to go to a higher-ranked school on loans than going to a lower-ranked school for free. Even though all numerically ranked law schools provide the same education (there have been several studies indicating this), employers really do prefer Tier 1 schools to all other law schools.
I used to tell people that if you should stop looking at law school if you scored below 155 on the LSATs. However, schools are starting to look more at GPAs so by the time you start applying to law schools, you might not have to worry about LSAT scores so much.
Now, GPA, which was your question. GPA is key. Now, Law school admission offices do look at where you did your undergraduate work and what your major was and will take that information into account. A lower GPA in a hard science from a great college will be given a fair standing from a good GPA from a pretty good school in a humanities major (this may sound mean to humanities majors but admission offices are impressed by science degrees. Many lawyers are bewildered by the sciences and some fields in the law require a hard science background). Now, when I say low GPA, I'm still referring to around a 3.0, so your grades can't be that low but there is still some wiggle room.
So, for your situation, it depends. Do you like Cornell? If you do and you are sure you can pick up your GPA, then stay. If you don't like it, go somewhere else but know that you will need to have higher grades to counteract any perceived drop in the quality of the school.
I think that should answer your question but again, make sure you want to go to law school. Too many people are going to law school for the wrong reasons and finding themselves in bad situations when they finally do graduate. Hopefully, that won't happen to you.
"There's no point being grown-up if you can't be childish sometimes." - The Fourth Doctor, Doctor Who