First, I am sorry to hear your father’s illness.
Your priority date is the date when USCIS received your I-130 application. Your approval notice should clearly state your priority date on I-797 form. If you are under F-1 category and have a priority date on May 2001, you should stick with your original plan by going through US consulate because it normally issues immigration visa faster than AOS. F-1 has stop moving on April 22, 2001 for a few months, unfortunately you have to wait your priority date earlier that visa cut-off date. At this stage, you need to make sure that you maintain a good standing immigration record since you are on B-1/2 tourist visa and communicate with the National Visa Center to pre-process your immigration application. The NVC normally starts to process an approved immigration case a year before your priority date becomes current. Once the NVC sends your immigration applications and financial support to the U.S. consulate, you just need to wait for your interview.
Here is consulate process:
1. Call the NVC immediately at 603-334-0700. You need to provide your USCIS receipt number on your I-797 approval notice. The NVC should already assign you a NVC case number that links to the U.S. consulate in your home country if USCIS has been forward your approval to them.
2. The NVC should send you DS3032 form and Affidavit of Support forms to your U.S. address as your request. You need to fill them out and send them back to the NVC process center.
3. Once the NVC finishes administrative review on your applications, your case will be forward to the U.S. consulate for immigration interview. Again, the U.S. consulate only schedules an interview after your priority date is current.
Use the link below as your guideline.
http://travel.state.gov/visa/immigrants/types/types_1309.html
If you have decided to use AOS, you need to call the NVC to hold your file. When the priority date is current, you can file I-485 for AOS. You can estimate your local process time from USCIS site after you file your I-485, but process times are various case by case.
https://egov.immigration.gov/cris/jsps/index.jsp
Good luck.