Though LooteKukur might be right, from my experience, I would not rely anything that goes in Nepal at face value. 7 days might be the wait time right now, but once you get there you might find out that it changed. Who knows what goes on in Nepal these days. And rules and system changes there very frequently as you may already know. Having said that, I would like to give you some advice from my experience as I was in the same situation a year ago.
You need to fill out visa application form DS157 (please double check). You can find out which forms to fill out from the homeland security website or by simply searching in google. Attached a passport size picture on it, sign it and mail it to your parents or some one you know in Nepal. Along with the form, you need to send copies of your passport, your previous visa/s, your OPT card, your H1B approval form, a letter from your employee stating your job position, and one extra photo. If you have time, you can either mail it through regular mail (which I would not recommend given the situation of postal system in Nepal), or go by UPS, or FedEX and express mail it. Though it is expensive (I think I paid more than $50), it will get there in less than a week and give them a contact number in Nepal that they can call for someone to come and pick it up from their office. And also ask the person in Nepal who will go to the bank to pay for the application fee, to tell them that since you are only coming for 2 weeks, they could only come with copies of documents since you will need the original for your travel.
It worked for me.
And don't forget, once you get your visa stamped, to go to the Labor Department (Shram Bevagh) to get the work permit to work in US (I know it is ridiculous). Or else they might not let you board the plane while flying out of Nepal.
GoodLuck!!
