Seema, I had a three year degree from Nepal too. But i was lucky to be accepted in a Masters program after a semester of undergraduate studies and completed the MS in 3 semesters. Although WES (or similar agencies) will evaluate your degree to be equivalent to 90 credits, most colleges require you to study 50-60 credits more to earn a US Undergraduate degree. if you don't want to spend 2 years in a US university and/or hard earned $, ask someone to admit you in MBS (TU) back in Nepal (they don't require you to be in the class), go home to take the first years exam, pass the exam and get your degree evaluated through WES (WES will evaluate your degree as equivalent to a four year degree from us). With >= 3 GPA and satisfying toefl score, You will be eligible to be accepted as a graduate student in most colleges in US or you may choose to take a year worth of remedial course to be eligible to sit in CPA exam (Since you studied BBS in Nepal).

Don't lose your hope, choose a path that is most suitable for you.