Hello. Thank you for using our service. All I ask is that before you sign off, you rate me positively. If you are inclined to use the "poor service" or "bad service" options, please ask follow-up questions first and give me a chance. Sometimes the law doesn't have a good solution, but I will try hard to find it if it is available.
This is quite common and not difficult to do. You would have to file an I-539 which can be found here:
You would have to explain the following:
1) How much time do you need?
2) Why do you need you so much time?
3) Why you couldn't do what you needed to do during time that you have already had?
4) How will you be supporting yourself for this additional time since you are not allowed to work?
5) What STRONG ties do you have to your home country to ensure that you will go back?
6) What preparations have you made to go back?
As long as the I-539 is pending, you are still in legal status even though your I-94 expires.
Please let me know if you have additional questions and please do not forget to rate my service to you (not the state of the law) as that is the only way that I can get credit for my assistance. Even after you rate the service, I can still answer additional questions for you without additional charge. If you do rate me positively, a bonus is always appreciated. If you would like to request me in the future, just go to http://www.justanswer.com/law/expert-guillermosenmartin/. Thank you!