A few suggestions/strategies to get into a top 20 grad school with low GPA:

--score in top 5% of GRE exams for the year of application

--enrol in a similar program at the current or other institution with intention of taking a few courses to prove that your 2.5 gpa does NOT truly represent your academic ability

--pass Level I of CFA exam; this proves that you have a fundamental background- a prerequisite for grad school

--if your current institution ranks in top 5 undergraduate finance program, GPA alone is never a factor- the grad admision committee may look at your extracurriculars, i.e. did you participate in a national case competition and win a 1st prize, were you a president of a club that was considered influtential, did you work in finance or a professional related field while attending classes, etc. Also, ensure to mention any factors that may have contributed to the low GPA, i.e. illness, family matters/emergencies, finances, etc. These should only be mentioned if applicable- honesty is important.

I am assuming that you want to apply for a MSc finance program- and not a MBA. If it's the latter I would definitely advise against it, as you will need get into top 20 with at least 3 years of work experience regardless of your GPA (there are exceptions with a good GPA- but the value of attaining MBA without any work exp is nil in my opinion).

Good Luck!

JP