Well...not exactly. You should definitely worry about your GPA. Higher GPA means admission to better graduate programs. And below a 3.0 typically disqualifies people from any graduate program. I'd certainly shoot for as high a GPA as you can possibly get. Also make sure you study hard for the math GRE. You have to take both the general GRE (which consists of vocabulary and basic math) and the math subject GRE to get into grad school. The general GRE isn't something you should take terribly seriously (chances are that you'll ace the math portion of the general test). In fact at the school where I did my undergrad math degree, the department stated that they didn't even look at the general GRE results at all when admitting grad students. But they look closely at your math subject test score, because the subject test covers topics like calculus, advanced geometry, algebra, analysis, etc. So make sure you do well on the subject test.
You'll probably want to apply directly for a PhD program, since you want to be a professor. As far as coursework goes, I would take two semesters each of algebra and analysis, as well as topology. Algebra, analysis, and topology are the "big three" subjects that grad schools look for (at least from what I know), so a strong background in this would definitely be to your advantage. Now, maybe you're far enough into your program that you don't have the time to take these courses. If so, then you may want to do a master's degree immediately after you graduate, during which you'll take the necessary coursework for a PhD program without having to pay for school (grad school is free). Master's applicants typically only need to have strong coursework in differential equations, advanced calculus, and linear algebra.
Finally, start doing research with a professor, this spring if possible. You'll need three letters of recommendation, and at least one should come from a professor who is familiar with your research abilities.
Well, I hope this helps.