Visa extension in Qingdao

Hi there. I just arrived in Qingdao last week on a double-entry L type one valid for 6 months with 30 days' stay per visit. As my husband is working here at the moment, is it possible to extend my first entry to more than 30 days before I do my exit, without losing the validity? Is it possible for me to apply for another one that will allow me to stay longer than 30 days?