J-1 extension

[mihau78]

Hi, I have a question, I am a research scholar from Poland, on J-1 visa working at a University. My visa stamp in passport expires mid October, but I already have a new DS-2019 with prolongation of my Program till August 2020. So as far as I do not leave USA, I can legally stay here and work with new prolonged DS-2019. But when I plan any trip outside USA (foreign conference, home visit) I need to apply for a new visa stamp in my passport. Is there any option to obtain it here, without going to Poland and US Embassy in Warsaw? Through USCIS for example?
If not, and I have to go to Poland for a new visa stamp, another question: I have scheduled a flight to Poland in December, I cannot get any holiday leave earlier. That means that when I leave the States, it will be around 2 months after expiration date on my visa stamp (but the new DS-2019 will be valid till 2020). So, could this produce any problems while applying for a new visa stamp in my passport, to come back to USA? Or should I get another visa stamp in my passport without any problems?
My actual I-94 says D/S for my stay period, and actual visa stamp in my passport allows multi cross the border.
Thank you for your help!

[newacct]

You cannot get the visa in the US (there would be no point as visas are only for entry). If you leave the US you do not necessarily have to go to Poland to get the visa; technically you could go to any US consulate, but it may be harder to get in a third country. How long the visa was expired is irrelevant; visas are only for entry and you didn't need to enter the US (because you were in the US).