My wife is on F2 visa. She is thinking about joining the Graduate school sometime next year. She already have a 3 year Bachelor's Degree in Microbiology from TU. 
I dont know if its required but she has already attested her transcript, certificate and syllabus from TU for the credit evaluation here in US. We are thinking about sending those attested documents to WES but not sure weather we really need to do that or not. 

Can anybody please suggest me what are the steps to take in order to get her into the Grad school and change status from F2 to F1?  And what problems she may face since she has a 3 year bachelors degree? It would be great if I coul hear from somebody who was in a same boat. Thankyou.

I would suggest you go to the international students center of the university you are trying to apply and request for an appointment. You would then explain what you are trying to accomplish and they should be able to help u with that. 3 years bachelor wouldn't suffice for Bachelor equivalency in US. Generally you would have two options either to get admitted for Bachelor program and complete it. Or try to get in Masters program but then will have prerequisites. The prerequisites could be accounting around more than 20 credits in general. This would certainly depend upon the type of university. Regarding the F2 to F1 , as soon as your wife is accepted by college as student she would be issued an I20 and reported in SEVIS . The status is adjusted to F1.

 Thanks for the reply perrybhadra. I'm still not sure which university she will be attainding. So mean while do you thing it will help to do the WES evaluation? or generally Universities themselves evaluate the credits from Nepal?

U need to decide which program and university to join. I don;t think WES evaluation will be valid for all universities anyway. They have the list there if your college is not there it might not make any sense. If you are planning to go some local university walk to the university and discuss about it they should be able to help u . u might need to provide transcripts as well course syllabus. And universities will have their own standard some might say they will transfer all 90 credit course , some might say they won;t transfer more than 30 or even none and they might be willing to negotiate. It all depends. 

 Thanks again perrybhadra. Right now we havent even decided what major to take or which university to go. Since she have 3 yrs degree, we are not even sure which university will accept maximum credit towards her bachelors degree . I thought WES evaluation is accepted every where but it seems like its better to decide which university to go first before going through the WES evaluation.

Any ways do you happen to know any university which accepts maximum credits from bachelors from nepal so that she dont have to take too many pre-requisits for masters? Thank you again.