Get a 15 day tourist visa stamped on arrival at TIA. It'll cost you $25.

After 13-14 days or so, go to the immigration office at Dilli Bazaar with your mom or dad to get "relation visa stamped on your passport"

You'll require :

1. Relationship Verification Certificate
2. Copy of your parent's citizenship.
3. $5/month ($60/6 months if you want multiple-entry)
4. Copies of visa stamps on your passport (US). You can actually talk to the guy at photocopy store about this. He'll help you.

I'm a naturalized US Citizen that just got back after spending 7 months in Nepal. Good luck.