Yes, it is possible to have a DJ extended rather than revoked in this sort of situation, but it would not be the normal course of events. What is likely to happen depends so greatly on your underlying felony case, the facts of your DUI, the specifics of your progress on probation, and your DA in district and county court.
If you win on your DUI case, the petition to revoke your DJ would be dismissed (unless there were other grounds).
What you really must do, is get an attorney who is comfortable and capable of handling your district court revocation of the deferred and who is also a DUI attorney. This gives you the best chance of getting an offer that saves your DJ but then also provides you with the ability to go to trial to take your best shot at winning the DUI if you don't get a safe offer. A felony on someone's record can ruin their lives depending on their goals, education, etc. Get the best lawyer you can afford and see what you can do.
If you cannot afford to hire an attorney, apply for a public defender and make sure your county court PD talks to your District Court PD and fully explain the situation to both.
There are a lot of good DUI attorneys on Avvo, look through them and contact as many as you want and hire the one you can afford and is the best fit for you.
Good luck and feel free to contact me if you have any questions or need any clarification.
The DA files the motion to revoke your deferred judgment and sentence and chooses what consequences they want. Normally they want your DJS to be revoked and reported as a conviction at a minimum. However, the judge has final say and frequently can reject a deal that calls for the deferred to not be revoked and simply extended. In fact, I saw that just today in Denver County Court. So, both the DA and the Judge will have to agree to extend your deferred judgment and sentence, which is VERY unlikely. Many states do not even have a deferred judgment and sentence possibility (UT comes to mind) and it is an EXTREME privilege viewed by both judges and DAs (I served in both capacities for 7 years each). So, I would seriously hold out hopes of avoiding it from being revoked. The chances are slim to none. However, you DO need an attorney, as both the DA and the Judge will be pissed that you picked up a DUI while on a deferred.
The information provided in this answer does not create an attorney-client relationship. If you are interested in his legal services, feel free to call Chris at (303) 409-7635 at his law office in the Denver Tech Center. All initial consultations are free of charge.