What type of punishment am I facing with a class C felony - criminal threatening with a dangerous weapon?

A class C felony conviction in ME is punishable by 5 years in prison and/or a $5,000 fine. So obtaining an experienced criminal attorney is critical. Skilled counsel may be able to get the charged dismissed, reduced, or win an acquittal at trial. Certainly, at the very least, having an otherwise clean criminal record will go a long way in enabling your attorney to convince the prosecutor to deal more leniently with you. At this point you need to retain a lawyer ASAP. 

If money is an issue for you, you might qualify for representation by the Public Defender.  If you do not meet income eligibility requirements check to see if you qualify for assistance with Legal Aid.  If not,  then see if there is a law school legal clinic nearby; they often times have legal clinics that will take these type cases for free. Finally, contact the local Bar Association in the county in which this has all taken place; they may have a list of attorneys who will take your case "pro bono" (for free) or at least for a reduced fee based on your income/circumstances.