It is perfectly possible. You can go to mexico or canada to renew your visa. However, to do so you have to have a very strong documents. If you are graduate students and paid by your univesity for your tuition and living expenses you will get your visa renewal pretty easily. If you are leaving on your own, then they will ask you to go back to your country for the visa application. Remember as soon as you apply for visa renewal, your previous visa is not valid, no matter your previous visa has not been expired yet. If you want to go to mexico, there are agents they will charge you $100 and take you form hotel(USA) to mexico. they are quite good. I have not done yet but two of my friend did it. There was no problem in their case. Good luck