Bro, I know times over here are lot harder than they think back home. Tara ke garney, garnai parchha ni bro. Sounds like you have lot of responsibilities back home, including your sister's education expenses too. But, just like KKP mentioned earlier, education in Nepal is a lot cheaper than here. Kehi raamro bishaya nai padhaau, visa kahile laagchha laagchha, how do we know? Also, since you said she is just finishing her +2, this is the 'prime time' in a student's life as they can choose a field of study that will eventually shape a career. So, don't let her waste it. We have all seen what happens when we lose a couple of years due to wrong major or say just due to lack of opportunity; I'm not saying you can never recover from that, but it's lot better to have a continuation in the same field that you chose at the beginning.

I understand you're not trying to be cheap, but if you can afford, please take a wise decision and enroll her in a more-productive field of study at her undergraduate level.

Good luck!!