I assume you are thinking of applying for the Class of 2015 (entry in Fall 2013). You would therefore be 3+ years out of college by the time you apply. Your grades are arguably recent enough that they would still hold some weight in the evaluation process (as opposed to, say, someone with 10 years of post-graduate experience).
Note that the GPA is less important (even on a year-over-year basis) than the specific grades achieved in each class (hence the transcript requirement).
Objectively speaking, though the trend in your yearly GPA was generally positive, your academic accomplishment seem at first blush not to put you in the most competitive "tier." Luckily, the key in the admissions process is not to demonstrate that you are so much better than everyone else (however "better" is defined or measured), but that you are capable of tackling a rigorous, analytical MBA program at a world-class institution.
What I think your consultant was trying to suggest is that you consider taking a class to demonstrate your current academic aptitude, interest in business, and seriousness in the application process. Don't think about the idea of taking an accounting or finance class at a community college as an attempt to "offset" past suboptimal grades, but more as a credible, tangible demonstration of present aptitude. Naturally, the more rigorous the program in which you enroll, the more credible your argument for being ready, now, will become.
At this point in time, if you do not make the decision soon to enroll in a class - and intend on applying in R1 or maybe R2, you may be better off focusing more of your time on constructing good essays (including an optional essay) and crafting a strong message across your other application submissions and recommendations.
Whatever you decide, just remember that you cannot change your past. All you can do is demonstrate that your present and future are bright, and that weaknesses in your past can - and have been overcome - as evidenced by clear, tangible examples and clean communication.