do they really have a case?

i have been charged with theft yet i tried to pay twice before i called the district attorney before a warrant was issued and asked him a third time if there was a way to pay this since noone know how and even offered to pay it through the courts. he told me they couldnt help then magiclly a warrant was issued three days later. with him as the DA. now my questions... 1. Do they really have a case? and 2 can i ask for the DA to be put on the stand as a witness since he can be crutial to my defence? and 3. is it possible since it is a very small town and a jury has a extremey high likelyhood of being bias. since its a big time public case and the whole town knows to ask it be moved to a different judicial district? tHANK YOU GREATLY