pamoshtnik,
Why is her student visa expiring after only 3 months? Which country is she from?
A B-1 Business Visa does not allow you to work and she wouldn’t be eligible anyway for the purpose that you described. Her best chance would be a B-2 Visitor Visa but she will have to leave the country before she can apply.
If she were to be approved for a visitor visa, she would usually be allowed to stay for up to 3 months or possibly up to 6 months in some cases. She wouldn’t actually know how long she would be allowed to stay until she arrives in the U.S. She would NOT be allowed to work or earn any wages while on a visitor visa.
Obtaining a visitor visa can be extremely difficult for citizens of certain countries, especially for younger single women. To be considered favorably for a visitor visa, it is extremely important that she depart the U.S. BEFORE her student visa expires. She may have to submit a lot of documentation to prove that she will only be staying for a short time, but her compliance with previous visas will be very important when considering her case.
Check with the U.S. Embassy Web site in her country for more instructions on applying for a visitor visa.
Ray