You will need to go to the PSB Entry/Exit bureau with jurisdiction over your residence - most of the administration of the visa types are handled through them - and NOT the overseas consulates. I've been here since Jan., 2011 without having to make a border run or leave the country. The visa and/or residence permit that you get from the PSB will allow an unlimited stay. Work permits are another story. You will need to talk to the PSB there, also. Normally, a work permit is tied to a specific employer. I'm not sure what they do for general work like what you want to do - hopefully, they can help you there as well.