The DA must prove that you were actually driving to get a DUI, and that you didn't drink between the time you stopped driving and when the police arrived to investigate. It seems like the DA will need the driver of the other vehicle to establish you as the driver (for both the Hit & Run and the DUI) and to establish you didn't drink AFTER driving. It also depends as to what you may have admitted to police. You also may be able to get the H&R dismissed if you pursue what's called a "civil compromise" wherein you get a declaration from the other party that the damages have been paid for and he doesn't object to the charge being dismissed. This requires the other guy's cooperation, so hopefully he has cooled off and you have an attorney who can get him to work with him. Ultimately, the cases has some good issues. I recommend getting an experienced DUI attorney to defend you.
Disclaimer: The response above does not form an attorney-client relationship, nor is it intended to be anything other than the educated opinion of the author. It should not be relied upon as legal advice.
First thing, do not discuss your case with anyone but your attorney. Anything you say to anyone but your attorney can be later used against you. Your attorney can act on your behalf to explain the case to you so you can make an informed decision about how you want the case to be resolved.
First, you should be careful about the information that you post where the public can see it. You have no expectation of privacy in the information you reveal. So, do not make statements like "I did a hit and run." Call an attorney and arrange a private consultation.