Hi Biswajit.. for changing a stream after 2 years will be little challenging.. Relevant experience in the field (credit, iBanking - IB, Equity Research-ER) is what you should be targeting with CFA for IB and ER.. and FRM for credit .. trying getting into a boutique investment bank (after CFA).. they don't pay much but the exposure will be good in the long run for a career in the relevant field.. in short just the degree won't help much.. trying getting relevant experience (with a compromise on the package) and keep clearing the levels of certification.. It is generally a tough path to follow.. but the long term retuns will make your effort worth it

the best course is one which suits ur interests and complements ur strengths. various options cud be cfa, cpa, ncfm or other such professional courses. any of these course will help u only if u put in ur best efforts to excel in them. so introspect nd do some basic ground work and then decide which course u want to go for.