I did the same thing in Jan..
Both hkrishna and C. Ronaldo..

What I did was,
1) I filled the form DS-160 online. COmpleted the form.
2) Went to this website and created the account to schedule interview. It would basically ask for your confirmation no from DS-160 and your basic information. << wait 24 hours filing DS160>> http://www.ustraveldocs.com/np/ .. then from there you can get CGI receipt,
3) Ask someone from nepal to pay for that CGI receipt. (FYI: It will be expiry date), if expired, generate again.
4) once paid, after few(give 24 hrs), you come back to the same website, and schedule your interview. << Be sure to save the receipt as you need to present during interview day)..
FYI: We pay in the investment bank , NO MORE IN NABIL BANK.

5) Once approved, basically they say 3 days, but I got the next day only. I got email saying pick up your document from Investment bank in Durbar marg. Then done.

Yes 2 weeks is enough if you do the above steps,. Before going nepal if you have interview date, that is perfect. I went for two weeks, even got married and came back :)

Any question buzz me : amriju {at} gmail.com