To renew your Visa you'll have to go back to Nepal and re-apply again. The process is Exactly same as you did when you applied for your VISA first time in Nepal.
Go to Nabil Bank , get the interview data and appear for interview.
You may get it or You may not.
If you ask me , what are the chances if you are already studying here ?
The answer is, there's no chance or probability in getting VISA, it's either YES or NO.

Good Luck.